In this story ten lepers were healed by Jesus, but only one comes back to express his gratitude. The emphasis of this story is not merely on gratitude as a virtue. Jesus gives us many good gifts, but God’s intention is that, as we encounter his loving kindness, it would ultimately bring us back to him so that we can totally be made whole.
When the Israelites were in the wilderness it was easy to remember that they needed God day by day because they were living in tents and God was sending them manna and quail. God wanted the Israelites to always remember that they are dependent on him, even when they were living in the Promised Land. God commanded that they should have an annual celebration called Sukkot to remember and celebrate his provision. By celebrating the good things that God has done for us we are reminded that we can put our trust in him.