Herod's Unlawful Oath
"The king was exceedingly sorry, but because of his oaths and his guests he did not want to break his word to [Herodias' daughter]. And immediately the king sent an executioner with orders to bring John's head. He went and beheaded him in the prison and brought his head on a platter and gave it to the girl, and the girl gave it to her mother" (vv. 26–28).
In refusing to obey Herodias' desire to have John the Baptist executed, Herod Antipas showed good discernment that John was a holy prophet and should be protected (Mark 6:14–20). For a time, Herod was able to keep John safe, having imprisoned him at Macherus, the fortified palace located east of the Jordan River. Yet Herod was not able to save John's life in the end, for the character of the king was not strong enough to preserve John when doing so might make him look weak before others.
In today's passage, we read that the order to have John killed came after the celebration of Herod Antipas' birthday. There is some question as to whether the term "birthday" in Mark 6:21 refers to the annual celebration of Herod's birth. It is possible that the word could mean the date that Herod took the throne over his portion of the kingdom of his father, Herod the Great; however, it is more likely that the word refers to what we customarily think of as a birthday. In any case, on the day of the celebration, we read that the daughter of Herodias, who was named Salome, did a dance for Herod Antipas that pleased him greatly. The fact that Salome was Antipas' stepdaughter and niece, along with the implication that the dance was almost certainly sensual, shows the depths of depravity to which Herod could sink. But the immoral nature of the dance and relationships involved was not enough to keep Antipas from promising Salome anything up to half his kingdom, a proverbial way of stating that he would give her anything that was in his power to give (vv. 22–23). After conferring with her mother, Salome asked for the head of John the Baptist on a platter (vv. 24–25).
Herod, of course, should have refused. However, he had vowed before witnesses, including people of importance in Judea, to do whatever Salome asked, and Herod did not want to lose face or appear untrustworthy before potential rivals. So, Herod had John executed (vv. 26–29).
Scripture commends the making and keeping of lawful oaths and vows (Num. 30:2), and that means that there are some oaths and vows that we should not make or keep. A vow to sin is unlawful to begin with, and the only way of honoring God in such a circumstance is to break the oath. But Herod saw his reputation before other men and women as more important than righteousness. He therefore compromised the truth and had John killed anyway
Coram Deo
We should not delay keeping the oaths and vows that we have made. However, that applies only to lawful oaths and vows. Oaths and vows made to commit sin are not to be kept. Instead, we should repent for making a sinful vow and then pursue righteousness. Such repentance is evidence of the work of God's Spirit in our lives.