First off, St. Patrick's life in very broad strokes: He was born in Britain in the 400's and raised a Christian. While he was still a child he was kidnapped and became a slave in Ireland. After spending six years or so in captivity, he escaped and returned to his family in Britain. There, he studied for the priesthood and received a vision instructing him to return to Ireland. So he returned as a bishop and proceeded to convert the Irish to Christianity, facing much persecution along the way.
Our Gospel today shows Jesus healing a lame man on the Sabbath, and from this point on "the Jews" (St. John's term, not mine) begin to persecute him. "The Jews" will be the antagonist throughout the rest of John's story.
Both Jesus and St. Patrick treated those to whom they ministered better than they deserved. If Jesus was operating under human terms of "fairness," then he could have quite fairly washed his hands of the Jews that were persecuting him. And the same thing with Patrick. He had no reason to return to the people that had enslaved him. It would have been fair of him to never return to that land. But both had moved beyond a human concept of fairness into a realm of self-sacrificial love. They both sought the good of their persecutors, even if it meant more harm would befall them.
This is what we are called to do as Christians, because God could quite fairly wash his hands of us at any time. We abuse and ignore his gifts to us so often, God could quite "fairly" just stop extending them. But he doesn't. Because God isn't fair, God is love (1 Jn 4:8). Because we are so undeserving of God's love, but he loves us anyway, we are called to extend that unfairly-given love to the world. St. Patrick showed us how.
S. Patricium, ora pro nobis.