He took to wife Jezebel - This was the head and chief of his offending; he took to wife, not only a heathen, but one whose hostility to the true religion was well known, and carried to the utmost extent.

1. She was the idolatrous daughter of an idolatrous king;

2. She practiced it openly;

3. She not only countenanced it in others, but protected it, and gave its partisans honors and rewards;

4. She used every means to persecute the true religion;

5. She was hideously cruel, and put to death the prophets and priests of God;

6. And all this she did with the most zealous perseverance and relentless cruelty.

Notwithstanding Ahab had built a temple, and made an altar for Baal, and set up the worship of Asherah, the Sidonian Venus, which we, 1 Kings 16:33, have transformed into a grove; yet so well known was the hostility of Jezebel to all good, that his marrying her was esteemed the highest pitch of vice, and an act the most provoking to God, and destructive to the prosperity of the kingdom.

the house of Baal

2 Kings 10:21,26,27 And Jehu sent through all Israel: and all the worshippers of Baal came, so that there was not a man left that came not...

Whether a Vow Consists in a Mere Purpose of the Will?
Objection 1: It would seem that a vow consists in nothing but a purpose of the will. According to some [*William of Auxerre, Sum. Aur. III, xxviii, qu. 1; Albertus Magnus, Sent. iv, D, 38], "a vow is a conception of a good purpose after a firm deliberation of the mind, whereby a man binds himself before God to do or not to do a certain thing." But the conception of a good purpose and so forth, may consist in a mere movement of the will. Therefore a vow consists in a mere purpose of the will. Objection …
Saint Thomas Aquinas—Summa Theologica