'Vowed' in the Bible

It happened at the end of forty years, that Absalom said to the king, "Please let me go and pay my vow, which I have vowed to Yahweh, in Hebron.

For your servant vowed a vow while I stayed at Geshur in Syria, saying, 'If Yahweh shall indeed bring me again to Jerusalem, then I will serve Yahweh.'"