Vowing a Vow

In the book of Judges, the concept of "vows" comes up in the record about Jephthah.  He made a vow to God that if God gave victory to him to defeat the Ammonites, he would offer a burnt offering of the first thing that came out his door upon returning home:

30 And Jephthah vowed a vow unto the Lord, and said, If thou shalt without fail deliver the children of Ammon into mine hands, 31 Then it shall be, that whatsoever cometh forth of the doors of my house to meet me, when I return in peace from the children of Ammon, shall surely be the Lord's, and I will offer it up for a burnt offering. Judges 11:30-31

As the record goes, his one and only daughter came through the door. He had just fought an enemy whose main god was appeased by child sacrifices. Many scholars believe that Jephthah's vow meant that his daughter would be dedicated to serve in the temple the rest of her life and there are some who believe she was an actual burnt offering. Irregardless, God did help to deliver the enemy into his hands, but I have issues with the 'vow' part. The way this reads sounds like an 'I will do this, if you will do this' proposition. Are we taught in God's word somewhere to pray this way????

Things digress in the book of Judges. Israel went from a God-only culture to a God plus gods of the surrounding culture to then to the stage of forsaking God and worshipping the idols of the culture around them:

6 And the children of Israel did evil again in the sight of the Lord, and served Baalim, and Ashtaroth, and the gods of Syria, and the gods of Zidon, and the gods of Moab, and the gods of the children of Ammon, and the gods of the Philistines, and forsook the Lord, and served not him. Judges 10:6

Jephthah's 'vow' to God seems off to me. God does not do things because of bribes or manipulation. God delivered them because of his love, compassion and grace when they trusted and listened to him.

Jesus Christ talks about oaths in Matthew 5:33-37:

33 Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths: 34 But I say unto you, Swear not at all; neither by heaven; for it is God's throne: 35 Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King. 36 Neither shalt thou swear by thy head, because thou canst not make one hair white or black. 37 But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.

James 5:12 says essentially the same thing:

12 But above all things, my brethren, swear not, neither by heaven, neither by the earth, neither by any other oath: but let your yea be yea; and your nay, nay; lest ye fall into condemnation.