Deuteronomy 29:19

19 `And it hath been, in his hearing the words of this oath, and he hath blessed himself in his heart, saying, I have peace, though in the stubbornness of my heart I go on, in order to end the fulness with the thirst.

Deuteronomy 29:19 In-Context

17 and ye see their abominations, and their idols, wood and stone, silver and gold, which [are] with them,
18 lest there be among you a man or woman, or family or tribe, whose heart is turning to-day from Jehovah our God, to go to serve the gods of those nations, lest there be in you a root fruitful of gall and wormwood:
19 `And it hath been, in his hearing the words of this oath, and he hath blessed himself in his heart, saying, I have peace, though in the stubbornness of my heart I go on, in order to end the fulness with the thirst.
20 Jehovah is not willing to be propitious to him, for then doth the anger of Jehovah smoke, also His zeal, against that man, and lain down on him hath all the oath which is written in this book, and Jehovah hath blotted out his name from under the heavens,
21 and Jehovah hath separated him for evil, out of all the tribes of Israel, according to all the oaths of the covenant which is written in this book of the law.
Young's Literal Translation is in the public domain.