How could Jephthah give his daughter as an offering?

Please explain Judges 11:31: “Shall surely be the Lord’s, and I will offer it up for a burnt offering.”

We know the story of Jephthah’s vow. It has been the subject of much heart searching and enquiry. Certainly there is something mysterious about it as it stands. Was Jephthah’s daughter really offered up as a burnt offering? This has been taken for granted and the story has been quoted to show the low morality of the times and the general need of humanity for the blessings of further “evolution” in their religious beliefs and practices! That the daughter was ever offered up as a burnt offering, however, can be proved neither by the story nor the morality of the times, but only that she bewailed her virginity. That is, she is supposed to have been thinking of this,when she might well have been thinking of losing her life. It would be like a convict about to lose his head, bewailing that they had cut his hair too close. I think the morality of Jephthah and his fellow-Israelites would probably compare very favourably with that of London or any other great modern city, and would certainly be better than that of some of the evolutionary, modernistic teachers, who while accepting a salary to preach what at the most solemn moment of their lives, they declared they unfeignedly believed, are now using their influence to undermine—the foundation truths of Creation, the Fall, Atonement, the true Deity of Christ, etc. All that we learn is that Jephthah is said to have met his daughter, and to have exclaimed: “I have been brought very low.” This was because she was his only child and therefore the only one by whom his name could be preserved. No doubt he was deeply moved: “I have opened my mouth unto the Lord and I cannot go back,” and the daughter, a true woman of faith, accepts the situation, and only asks that she may be allowed two months that she may go up and down and bewail—her life? No, again, her virginity. She returns at the end of the time, and “her father did with her according to his vow which he had vowed,” with what result? that she had died bravely and was buried? No, again we say, but that she never entered the married state. One would think this an unnecessary piece of information, if, in fact, she had been burnt alive, as some would have us believe. I will give one or two further reasons for believing that this is not the true meaning. (i) Human sacrifices were abhorrent to God’s mind. As for passing children through the fire in his honour, it was absolutely foreign to His intention. Jehovah’s words of this very thing are, “I commanded them not, neither came into My mind that they should do this abomination, to cause Judah to sin” (see Jeremiah 32:35, also Ezekiel 16:20, 21; Ezekiel 20:26, 3:). Can we suppose this man of God to do “such a thing”? (2) For Jephthah was, we see, a man of God, by verse i i, and also by the character of his remonstrance to the king of Animon. His name, too, occurs among the heroes of faith of Heb. ii. () It is distinctly said that “the Spirit of God came upon him” before this incident. Can we then suppose he would have been permitted to sacrifice his daughter in the way supposed, entirely out of harmony with the will of God? (ii.) I think the true solution is found in the margin of our Bibles, “Shall surely be the Lord’s, OR I will offer it up for a burnt offering.” Had it been his dog or other unclean animal, how could he have offered it up as a burnt offering? No, but he might have sold it and given the price to the Lord. This marginal reading is borne out by the disjunctive use of Waw (“and”) in Hebrew, which also has the force of “OR,” as in Exodus 21:6 (“selleth him, OR if he be found in his hand”), Ex. 21. 17 (“father OR mother”), Deuteronomy 24: 7 (“maketh merchandise of him, OR selleth him”); and of “WHETHER R,” as in Ex. 21. 31 (“WHETHER he have gored a son, OR have gored a daughter”). In all these passages, “and” would be out of place. It would seem clear that in Jephthah’s intention, to be “the Lord’s”, entailed a life of celibacy. There may have been some such custom current, to judge from this passage, though we know not of any command to confirm it. It is interesting to note the marginal reading of “lament” in the last verse of the chapter—”talk with”—the same verb, ”tinneh” which is translated “rehearse” in Judges 5:11