Did people in the Old Testament choose to die for God? That just sounds so pagan.
Leviticus 27:28"But no devoted thing that a man devotes to the LORD, of anything that he has, whether man or beast, or of his inherited field, shall be sold or redeemed; every devoted thing is most holy to the LORD. 29No one devoted, who is to be devoted for destruction from mankind, shall be ransomed; he shall surely be put to death.This is a very interesting question. There is one famous example of human sacrifice in the book of Judges where Jephthah makes a vow to offer a sacrifice to God if God will give him victory in an important battle.
And Jephthah made a vow to the LORD and said, "If you will give the Ammonites into my hand, then whatever comes out from the doors of my house to meet me when I return in peace from the Ammonites shall be the LORD's, and I will offer it up for a burnt offering." So Jephthah crossed over to the Ammonites to fight against them, and the LORD gave them into his hand. And he struck them from Aroer to the neighborhood of Minnith, twenty cities, and as far as Abel-keramim, with a great blow. So the Ammonites were subdued before the people of Israel. Then Jephthah came to his home at Mizpah. And behold, his daughter came out to meet him with tambourines and with dances. She was his only child; beside her he had neither son nor daughter. And as soon as he saw her, he tore his clothes and said, "Alas, my daughter! You have brought me very low, and you have become the cause of great trouble to me. For I have opened my mouth to the LORD, and I cannot take back my vow." (Jdg 11:30-35)Many have interpreted these verses to mean that the girl was devoted to live a life of celibacy in the service to the Lord. I think that since the vow that Jephthah makes is for a burnt offering that a burnt offering is the fulfillment of the vow. Also Jephthah takes his vow very seriously. So in this one instance we see that a girl was devoted to the Lord for a burnt offering and that her father followed the law to the letter by not ransoming her, even though she was his only child.
I'm not so sure that was the intent of the law, however.
When Israel was going into the land of Canaan, God instituted a 'take no prisoners' policy. All of the inhabitants of Canaan were to be obliterated. They were devoted, not to sacrifice, but to 'destruction from mankind'.
There was also the issue of conviction under the law. Those who broke laws that carried the penalty of death were devoted to destruction. They were not to go free. They could not be ransomed or bought from destruction because God demanded human blood for those offences. In other words, there was no animal sacrifice that was to be offered in the place of those under the penalty of death.
This brings the weight of our sins before us and teaches us about the death of Christ. Christ died for criminals under the penalty of the law. We could not be redeemed by silver, gold, or animal sacrifices. We could only be redeemed by the blood of a human. God must become man to redeem us.
But the law goes a step further. The one who was devoted to death must be the one to die. This is where our union with Christ comes in. When Christ died, I died. And when Christ rose again, I rose again with Him.
Finally, this law teaches us about the Christ who lived His entire life 'devoted to death'. Even when He was in the womb He was growing and developing in order that He might die. This points us to Christ's great purpose in becoming human and tells us that His death was not an accident or even a 'Plan B'. Christ came to die for our sins and in doing so to unite us with Him in such a way that it could be said that in Him I accomplished the law, I died to the law, and that I am a co-heir together with Him of all the promises and blessings that God has to offer.
Soli Deo Gloria