"And Jesus answered and said to him, 'Simon, I have something to say to you.' So he said, 'Teacher, say it.' 'There was a certain creditor who had two debtors. One owed five hundred denarii, and the other fifty. And when they had nothing with which to repay, he freely forgave them both. Tell Me, therefore, which of them will love him more?'" (Luke 7:40-42).
GRATITUDE FOR GOD'S FORGIVENESS IS A POWERFUL FORCE THAT MOVES US IN THE DIRECTION OF TRUTH AND GOODNESS. To the extent that we're aware of the magnitude of our sins and the love that had to be shown by God to make their forgiveness possible, we will be motivated both to seek Him and to serve Him. If our motivation toward God is not what it should be, here is the key to progress: we must increase our love by increasing our gratitude.
Paul spoke of the "constraining" or "compelling" effect of Christ's love for us. "For the love of Christ compels us, because we judge thus: that if One died for all, then all died; and He died for all, that those who live should live no longer for themselves, but for Him who died for them and rose again" (2 Corinthians 5:14,15). And the love of Christ is that which compels us even before we've been forgiven of our sins. It is our recognition of His love and our joyous anticipation of gratitude to Him that move us to respond to the gospel in the first place.
It is important to remember the proper order of these things. God's love comes first, and then our gratitude and love. If we're not careful, we may lapse into thinking that God confers forgiveness upon us because we are those who love Him. However, just the opposite is true. "Love is not the cause of forgiveness. Forgiveness causes love. The more we are forgiven, the more we love" (William Tyndale). John said simply, "In this is love, not that we loved God, but that He loved us" (1 John 4:10). "We love Him because He first loved us" (1 John 4:19).
In general, gratitude comes from a sense of our emptiness and need. If we're proud and self-sufficient, and if we suppose there is little about us to be forgiven, then there will be little gratitude in us -- and consequently little love, little seeking of God, and little in the way of service to Him. Without the power of gratitude, we fight a losing battle.
"A true Christian is a man who never for a moment forgets what God has done for him in Christ, and whose whole comportment and whole activity have their root in the sentiment of gratitude" (John Baillie).