Paul certainly understood God's message in terms of His unfailing grace. As a result, he took "pleasure in infirmities, in reproaches, in necessities, in persecutions, in distresses for Christ's sake: for when I am weak, then am I strong." II Cor. 12:9, 10. The title of this article is taken from verse 9.
Wouldn't we all like to know that when we're weakest or feel most inadequate, when we seem personally least able to do the good we would do, then we can be strongest in our reliance on God, firmest in our trust in His power, most steadfast in our recognition of His purpose being fulfilled.
I've come to the conclusion that we can feel this assurance as we understand more about grace. Paul must have understood it well. He refers to grace in his various epistles dozens of times. Perhaps he felt his vision on the road to Damascus and subsequent conversion gave him a special grasp of God's grace or unfailing love. He no doubt felt his life proved his words to the Romans: "Sin shall not have dominion over you: for ye are not under the law, but under grace." Rom. 6:14.