“Continue earnestly in prayer, being vigilant in it with thanksgiving.”
Several passages in the New Testament connect prayer and vigilance:
The Lord Jesus connected the ideas of prayer and watching in Matthew 26:41 “Watch and pray, lest you enter into temptation. The spirit indeed is willing, but the flesh is weak.”
It is abundantly clear that the flesh is weak when it comes to prayer!
Ephesians 6:18 “Praying always with all prayer and supplication in the Spirit, being watchful to this end with all perseverance and supplication for all the saints.”
I Peter 4:7 “But the end of all things is at hand; therefore be serious and watchful in your prayers.” Watch that you do not fall asleep while you pray. Watch so that your mind does not wander.
God wants the believer to be vigilant in prayer.
When a believer goes to prayer, he becomes a special target of the Devil. He will suggest evil thoughts while you are at prayer. He does not want us to pray so he will cause us to fall asleep. He puts anxious thoughts in our minds while we pray. We can fret, stew, and worry in prayer, although that is what prayer is supposed to alleviate (Phil. 4:6,7). The Devil is a supernatural foe to prayer.
One of the earmarks of carnality is prayerlessness (James 4:1). Carnality is a disease that only a Christian can catch. We are perfunctory in prayer until some crisis comes along. No one is sick, and our finances are in place, so why should I pray? When the crisis comes, we can pray very eloquently! Because we are reluctant to pray, God brings adversity into our lives.