Can you explain the story of Jephthah who made the vow to God and had to keep it...my question is did he use her ( his only daughter and child) as a b

This is a lesson that teaches us the consequences of "bargaining" with God. Jephthah did not need to make this bargain. God is sovereign and He was going to use Jepthah to defeat the Ammonites. There was no need for any bargaining. Jepthah put his entire house at risk when he made this vow...anyone who came out would have been the victim. Jephthah's punishment was God's silence and the loss of his daughter. This somewhat parallels the account of Abraham and his son, but the major difference is that God initiated the action with Abraham (and saved his son) while in the Jephthah account, God did not initiate the pact, it was totally unneccessary, and I believe it made Him very angry that Jephthah would make such a pact to begin with. As it played out, it definately broke the laws regarding child/human sacrifices...but this was Jepthah's sin, not God's.