Therefore, as God's chosen people, holy and dearly loved, clothe yourselves with compassion, kindness, humility, gentleness, and patience. Bear with each other and forgive whatever grievances you may have against one another. Forgive as the Lord forgave you.
Colossians 3:12-13
There are countless reminders throughout the Bible that forgiveness is essential to our lives as Christians, both in how we receive salvation and how we reflect God's holiness to the world. But I'm especially fond of this verse because preceding his urging of forgiveness, Paul outlines the other qualities of holiness that complement forgiveness: "clothe yourselves with compassion, kindness, humility, gentleness, and patience."
I think it's easy to identify kindness and gentleness with forgiveness, but we often forget about the other traits. We forget that forgiveness requires compassion - that we are all God's children and that He loves each and every one of us the same. We forget that it requires humility - letting go of our pride and realizing that we are all sinners, that it is only by the grace of God that we are saved from our sins, and that redemption is for everyone. And finally we forget that it requires patience - the patience to come to God and allow Him to shape our heart and the patience to allow Him to work in the life of our transgressor.
If we ask God to work on us in all these areas, I think forgiveness becomes the easy part. And once we have committed the act of forgiveness, Paul offers the icing on the cake, "And over all these virtues put on love, which binds them all together in perfect unity" (Col 3:14).