We are to ask forgiveness—this is the one petition to which most people object, and some attempt to escape from the prayer because of it. I am not particularly surprised that people criticize this petition more than any other. It is a very difficult one to pray, but let us remember that when Christ gave this prayer in His Manifesto, He commented only upon this petition. “For if ye forgive not men their trespasses, neither will your Father forgive your trespasses.” So we must neither get away from this petition, nor indulge in that criticism which attempts to accommodate it to our own failure…If we are unforgiving, in the necessity of the case God will not forgive us. There is no escape from it. Is not hatred the most dastardly and heinous of all sins—hatred, the thing that contradicts the essence of God which is love? If in my heart there is bitterness and malice and revengefulness what is the use of confessing other sins and expecting to be forgiven, nursing the while the most damnable sin? We who are children of God, subjects of the King, flock of the Shepherd, cannot be forgiven unless we forgive, for our refusal to forgive is the deepest and worst sin of all. I speak with such emphasis because I think the Church of Jesus Christ is cursed by an unforgiving spirit. 

The Practice of Prayer - G. Campbell Morgan