The Lord's Prayer most clearly expresses this condition, as we ask for forgiveness only as we promise to forgive, and after the Lord's Prayer in Matthew we have the lesson stressed, "For if you forgive others their trespasses, your heavenly Father will also forgive you; but if you do not forgive others, neither will your Father forgive your trespasses" (Matt.6:14-15). The words quoted above from Mark 11:25, it is important to notice, came immediately Jesus' teaching about the prayer of faith. Faith and a forgiving spirit belong together as conditions of effective prayer.
It is the merciful who can expect the mercy of God, as the `beatitude' in Matthew 5:7 puts it, and the same thing is implied when Matthew 5:23-25 speaks of the need of reconciliation with one's brother or sister before coming to worship God and offer gifts. In the same vein there is hardly a more powerful parable that came from the lips of Jesus than that of the unforgiving debtor in Matthew 18:23-35. Jesus who taught these things gave the supreme example of such forgiving as on the cross he prayed for the forgiveness of his enemies (Lk.23:34).
Every Christian counsellor knows that the spiritual lives of countless people are stunted, and in accord with this clear teaching of Scripture their prayers prevented from reaching heaven, by an unforgiving spirit. Resentments are held from year to year, and thus prayer is hindered. Forgiving, as Anthony Bloom stresses, means continuing to be forgiving. It is not just granting forgiveness at a moment of softening of the heart in an emotional crisis, but then subsequently taking back that forgiveness and continuing to nurse a resentment. (12)
There are prayers in Scripture from which the greatest lesson we can learn is that of frankness. Nothing can be hidden from the living God who sees and knows all about us. Therefore nothing need be hidden, and we can feel free, though with reverence, to tell God our situation as it is and how we feel in it. Such is the case with Moses in his leadership of the people. Initially he gave to God what he thought were good reasons why he should not assume leadership of the people and go to Pharoah to seek his people's freedom (Ex.4). Often later he expressed frankly to God his impatience with his people, "Why have you treated your servant so badly -- that you lay the burden of all this people on me?" (Num.11:11) Such is the case supremely with the prayers of Job in despair and despondency (e.g. Job 3, 9 and 10). In the so-called `Confessions of Jeremiah', we see this frankness with God finding most vivid expression (Jer.11:18-12:6, 15:10-21, 17:5-10, 14-18, 18:18-23 and 20:7-18). For few people the work of being prophet at such a time and in such a situation could have been harder then it was for Jeremiah, and he said so to the Almighty.
Many a faithful servant of the Lord has turned similarly with utter frankness to God, when faced with what seems the human impossibility of the task one is called to do. In the New Testament Ananias called to go to meet Saul of Tarsus, the arch-persecutor of Christians, told God frankly what he thought of such a commission (Acts 9:13). There was a similarly frank response in prayer of that same Saul of Tarsus when he had become a Christian and was called to preach the gospel that he had opposed so virulently (Acts 22:18-20).
Frankness in prayer is never rejected in the Bible, though the one who speaks frankly to God must be prepared for a frank answer. The passages that tell of all four examples given above - Moses, Jeremiah, Ananias and Paul - specifically give us the frank divine answers they received.