"When we become too glib in prayer we are most surely talking to ourselves." [A.W. Tozer]
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What Is Praying In The Spirit?
What Does It Mean To Pray Without Ceasing?
Many Words vs. Persistent Praying
"What Is Praying In The Spirit?"
Praying in the Spirit is mentioned three times in Scripture. First Corinthians 14:15 says, “So what shall I do? I will pray with my spirit, but I will also pray with my mind; I will sing with my spirit, but I will also sing with my mind.” Ephesians 6:18 says, “And pray in the Spirit on all occasions with all kinds of prayers and requests. With this in mind, be alert and always keep on praying for all the saints.” Jude 20 says, “But you, dear friends, build yourselves up in your most holy faith and pray in the Holy Spirit.” So, what exactly does it mean to pray in the Spirit?
The Greek word translated “pray in” can have several different meanings. It can mean “by means of,” “with the help of,” “in the sphere of,” and “in connection to.” Praying in the Spirit does not refer to the words we are saying. Rather, it refers to how we are praying. Praying in the Spirit is praying according to the Spirit’s leading. It is praying for things the Spirit leads us to pray for. Romans 8:26 tells us, “In the same way, the Spirit helps us in our weakness. We do not know what we ought to pray for, but the Spirit Himself intercedes for us with groans that words cannot express.”
Some, based on 1 Corinthians 14:15, equate praying in the Spirit with praying in tongues. Discussing the gift of tongues, Paul mentions “pray with my spirit.” First Corinthians 14:14 states that when a person prays in tongues, he does not know what he is saying, since it is spoken in a language he does not know. Further, no one else can understand what is being said, unless there is an interpreter (1 Corinthians 14:27-28).
In Ephesians 6:18, Paul instructs us to “pray in the Spirit on all occasions with all kinds of prayers and requests.” How are we to pray with all kinds of prayers and requests and pray for the saints, if no one, including the person praying, understands what is being said? Therefore, praying in the Spirit should be understood as praying in the power of the Spirit, by the leading of the Spirit, and according to His will, not as praying in tongues. 
See Tongues and the “Second Blessing”
Not everyone shares the opinion that the Pentecostal position on tongues is Biblical nor that the 'Second Blessing' is a blessing.
What is certain is that it is an issue of no small magnitude.
"What Does It Mean To Pray Without Ceasing?"
Paul’s command in 1 Thessalonians 5:17 to “pray without ceasing,” can be confusing. Obviously, it cannot mean we are to be in a head-bowed, eyes-closed posture all day long. Paul is not referring to non-stop talking, but rather an attitude of God-consciousness and God-surrender that we carry with us all the time. Every waking moment is to be lived in an awareness that God is with us and that He is actively involved and engaged in our thoughts and actions.
When our thoughts turn to worry, fear, discouragement, and anger, we are to consciously and quickly turn every thought into prayer and every prayer into thanksgiving. In his letter to the Philippians, Paul commands us to stop being anxious and instead, “in everything, by prayer and petition, with thanksgiving, present your requests to God” (Philippians 4:6). He taught the believers at Colossae to devote themselves “to prayer, being watchful and thankful” (Colossians 4:2). Paul exhorted the Ephesian believers to see prayer as a weapon to use in fighting spiritual battles (Ephesians 6:18). As we go through the day, prayer should be our first response to every fearful situation, every anxious thought, and every undesired task that God commands. A lack of prayer will cause us to depend on ourselves instead of depending on God's grace. Unceasing prayer is, in essence, continual dependence upon and communion with the Father.
For Christians, prayer should be like breathing. You do not have to think to breathe because the atmosphere exerts pressure on your lungs and essentially forces you to breathe. That is why it is more difficult to hold your breath than it is to breathe. Similarly, when we are born into the family of God, we enter into a spiritual atmosphere where God's presence and grace exert pressure, or influence, on our lives. Prayer is the normal response to that pressure. As believers, we have all entered the divine atmosphere to breathe the air of prayer.
Unfortunately, many believers hold their “spiritual breath” for long periods, thinking brief moments with God are sufficient to allow them to survive. The fact is that every believer must be continually in the presence of God, constantly breathing in His truths, to be fully functional.
It is easier for Christians to feel secure by presuming on - instead of depending on - God's grace. Too many believers become satisfied with physical blessings and have little desire for spiritual ones. When programs, methods, and money produce impressive results, there is an inclination to confuse human success with divine blessing. When that happens, passionate longing for God and yearning for His help will be missing. Continual, persistent, incessant prayer is an essential part of Christian living and flows out of humility and dependence on God. 
Also See Re-examining Revival - Why The Fire Hasn’t Fallen
A praying community - men and women who "with one mind were continually devoting themselves to prayer (Acts 1:14)" were the ones that experienced the fire of God on Pentecost. Unfortunately, the prayer meeting in the modern church is all but lost, buried under a sea of other programs, most nice, but completely irrelevant. There is no question that some churches do pray, some have a prayer ministry, and some have prayer meetings (all too often poorly planned and poorly attended). However, until we have prayer meetings devoted to seeking God's face we wil never experience revival.
What it Means to Pray without Ceasing? (Colossians 3:2)
Unceasing, incessant prayer is essential to the vitality of your relationship to the Lord and your ability to function in the world. But exactly what does it mean to pray without ceasing?
The first time someone hears about the concept of praying without ceasing it may conjure up the image of Christians walking around with their hands folded, heads bowed, and eyes closed, bumping into things. While certain postures and specific times set aside for prayer have an important bearing on our communication with God, to "pray at all times" obviously does not mean we are to pray in formal or noticeable ways every waking moment. And it does not mean you're supposed to devote yourself to reciting ritualistic patterns and forms of prayer.
To "pray without ceasing" refers recurring prayer, not nonstop talking. Prayer is to be a way of life - you're to be continually in an attitude of prayer. It is living in continual God-consciousness, where everything you see and experience becomes a kind of prayer, lived in deep awareness of and surrender to Him. It should be instant and intimate communication-not unlike that which we enjoy with our best friend.
To "pray without ceasing" means when you are tempted, you hold the temptation before God and ask for His help. When you experience something good and beautiful, you immediately thank the Lord for it. When you see evil around you, you ask God to make it right and to use you toward that end, if that is His will. When you meet someone who does not know Christ, you pray for God to draw that person to Himself and to use you to be a faithful witness. When you encounter trouble, you turn to God as your Deliverer.
Thus life becomes a continually ascending prayer: all life's thoughts, deeds, and circumstances become an opportunity to commune with your Heavenly Father. In that way you constantly set your mind "on the things above, not on the things that are on earth" (Colossians 3:2).
As said by WA. Criswell
You don't need your voice, you can pray in your heart. You don't have to have a place; any place is a good place. A kitchen corner is just as good as the most magnificent cathedral. Any time is a good time, while you're working over the sink, while you're busy about the duties of the house, while you're on the way to work or back away from work. Any time is a good time: early or late. Any hour, the door is open. We're not bound in our praying to any stated habit, any stated way, any stated time, or any stated place...
we can pray while our hands are busy: washing dishes, sweeping out the house, punching a typewriter, riding to town, coming back from work, selling goods over the counter, poring over these law books, out into the real estate world. All through the day we can breathe a prayer. All these things that we can ask God for in behalf of our church, in behalf of revival appeal, in behalf of the services, in behalf of the laws, in behalf of home and family, in behalf of the pastor, in behalf of the work of God in the earth, in behalf of our hospitals, our schools, our mission fields, our missionaries. How many times in the course of a day, while our hands are busy, can we ask Gods blessings? Praying without ceasing, our whole lives, a continuous intercession.
He also pointed out some Biblical examples of...
When Elijah said to his servant, "Go look." And the servant stood on the brow of Mount Carmel, looked out over the Mediterranean Sea, came back and said, "There is nothing." Elijah prayed again, and six times the servant came back from his lookout and said, "And there is nothing." And Elijah prayed the seventh time, and the seventh time the servant came back and said, "I see a cloud the size of a man's hand" (1 Kings 18:42-44). And Elijah replied, "There is the sound of abundance of rain." We are never to despair in our praying. We are to pray without ceasing.
Now look at this. In the parable of the importunate widow (Luke 18:1-8), she went to the unjust judge and bothered him and bothered him and bothered him until he was so weary of her he said, "I will do what this woman wants just to get rid of her." And He says that's the way we ought to be in prayer. Well, that widow was after one blessing, one blessing.
Now the story of the friend at midnight: he came and wanted some bread for a guest who had come at midnight, and he had nothing to lay before him. And he went to his friend's house and knocked at the door. And the fellow stuck his head out from the loft up there and said, "Who is that bothering me?" And the man said, "I have got a friend and he is hungry, I do not have anything to eat, and I have come to borrow a loaf of bread." And the man said, "Listen, I am in bed. And my children and my family are all asleep. Go away!" And he slams the window up there. And the fellow keeps on a-knocking, and the fellow up there in that loft, he says, "If I do not go down and give that fellow bread, he will keep me awake all night long." And he comes down and gives him everything he wants [Luke 11:5-8]. [Pray Without Ceasing-Pt.1. February 23rd, 1958 @ 7:30 PM. 1 Thessalonians 5:17
 Adapted from John MacArthur's Alone With God Pgs. 15-17.