6. He solemnly binds his soul with a bond that, if God work deliverance for him, the God of his mercies shall be the God of his praises, v. 9. He covenants with God, (1.) That he will honour him in his devotions with the sacrifice of thanksgiving; and God has said, for the encouragement of those that do so, that those that offer praise glorify him. He will, according to the law of Moses, bring a sacrifice of thanksgiving, and will offer that according to the law of nature, with the voice of thanksgiving. The love and thankfulness of the heart to God are the life and soul of this duty; without these neither the sacrifice of thanksgiving nor the voice of thanksgiving will avail any thing. But gratitude was then, by a divine appointment, to be expressed by a sacrifice, in which the offerer presented the beast slain to God, not in lieu of himself, but in token of himself; and it is now to be expressed by the voice of thanksgiving, the calves of our lips (Hos. xiv. 2), the fruit of our lips (Heb. xiii. 15), speaking forth, singing forth, the high praises of our God. This Jonah here promises, that with the sacrifice of thanksgiving he will mention the lovingkindness of the Lord, to his glory, and the encouragement of others. (2.) That he will honour him in his conversation by a punctual performance of his vows, which he made in the fish's belly. Some think it was some work of charity that he vowed, or such a vow as Jacob's was, Of all that thou hast given me I will give the tenth unto thee. More probably his vow was that if God would deliver him he would readily go wherever he should please to send him, though it were to Nineveh. When we smart for deserting our duty it is time to promise that we will adhere to it, and abound in it. Or, perhaps, the sacrifice of thanksgiving is the thing he vowed, and that is it which he will pay, as David, Ps. cxvi. 17-19.