Psalms 100 reminds us that we are to come to worship with praise and thanksgiving already in our hearts. Gratitude should be a hallmark of every child of grace. It is not enough to feel grateful — we should also express our thanks to God.
On the way to Jerusalem he was passing along between Samaria and Galilee. And as he entered a village, he was met by ten lepers, who stood at a distance and lifted up their voices, saying, “Jesus, Master, have mercy on us.” When he saw them he said to them, “Go and show yourselves to the priests.” And as they went they were cleansed. Then one of them, when he saw that he was healed, turned back, praising God with a loud voice; and he fell on his face at Jesus’ feet, giving him thanks. Now he was a Samaritan. Then Jesus answered, “Were not ten cleansed? Where are the nine? Was no one found to return and give praise to God except this foreigner?” And he said to him, “Rise and go your way; your faith has made you well.”
Luke 17:11-19 (ESV)