"Not lose heart" or "faint" (KJV) means to grow weary, to give in to evil, to turn coward. We must resist the human tendency of growing weary in prayer. We have a duty as the elect of God to pray. There are several major causes of losing heart: defilement, doubt, danger, distractions, and delay.

» The defilement of sin kills interest in spiritual exercises like prayer. Sin does not promote a good prayer life—in fact, it will stop it dead. "If I regard iniquity in my heart, the Lord will not hear" (Psalm 66:18).

» Praying with doubt is faithless, making the prayer useless. Doubting the inspiration of Scripture and the power of God hinders prayer (I Timothy 2:8). As prayer and faith go hand in hand, so do unbelief and not praying.

» Prayer must sometimes be done at dangerous times. Danger weeds out the coward from the courageous. Daniel faced real danger in praying, but kept on praying, even though it led to the lion's den (Daniel 6). Today, our dangers are varied, but the danger of embarrassment often affects people more than danger of physical harm.

» Satan is a master of causing distractions, especially during prayer time. Probably every saint has experienced his mind wandering, causing him to think about everything except what he should be praying about.

» Few things cause us to lose heart in praying more than delays in answers to our requests. Jesus uses the Parable of the Persistent Widow to teach us that, though answers often appear to take a long time in coming, we should persevere and not grow weary in praying to God.