Without prayer any relationship with God is impoverished because vital communication is lost.
Reasons for prayerlessness
Unbelief Ps 14:1-4 pp Ps 53:1-4 See also Job 21:15; Ro 3:11
Self-reliance Jer 17:5 See also Zep 3:2
Worship of other gods Dt 32:17-18 See also Jer 2:5-6,8
Guilt as a result of disobedience Ge 3:9-12 Adam and Eve did not respond to their sin by praying. On the contrary they sought to hide from God; Jnh 1:1-6 Jonah tried to run away from God.
Tiredness Lk 22:45 See also Mt 26:40 pp Mk 14:37; Mt 26:43-45 pp Mk 14:40-41
Discord in relationship 1Pe 3:7
Examples of prayerlessness
Joshua, after a great victory Jos 7:2-5 Joshua devised his own plan in attacking Ai and did not seek the Lord until after he suffered a disastrous defeat.
King Ahaziah, turning to idols 2Ki 1:16 See also 2Ki 1:1-6
The nominal religion of Israel Isa 43:22 This verse implies that prayer involves effort—the people only paid lip service to God. See also Isa 1:14; Isa 64:7
Israel trusts in other people rather than God Isa 30:1-2; Isa 31:1
Israel’s failure to repent of their sins Da 9:13 See also Isa 9:13; Jer 5:3
The lack of an intercessor among God’s people Eze 22:30
Consequences of prayerlessness
Alienation from God Jn 15:6 See also Ps 73:27
God’s judgment Zep 1:4-6 See also Jer 10:21
Disloyalty to Jesus Christ Mt 26:74 pp Mk 14:71 pp Lk 22:60 pp Jn 18:27 Peter had previously failed to pray in Gethsemane.
Spiritual poverty Jas 4:2 See also 2Ki 17:15; Jer 2:5
Ineffective ministry 1Sa 2:12 This literally means they had no fellowship with the Lord; 1Sa 12:23; Jn 15:4-5
Conflicts with others because of unfulfilled desires Jas 4:1-4