24Then the end will come, when he hands over the kingdom to God the Father after he has destroyed all dominion, authority and power. 25For he must reign until he has put all his enemies under his feet. 26The last enemy to be destroyed is death. 27For he “has put everything under his feet.”[c] Now when it says that “everything” has been put under him, it is clear that this does not include God himself, who put everything under Christ. 28When he has done this, then the Son himself will be made subject to him who put everything under him, so that God may be all in all.
This is from 1Corinthians chapter 15. In response to the question “what did Jesus lose/give up/sacrifice?”…when it says that “Son himself will be made subject” the word subject in the Greek is a military term meaning “to rank under”. What is being described here is the true sacrifice that Jesus made. He paid for the sin of the world on the cross, yes, but will continue to pay for it for all eternity by giving up his equality with the Father (he is still God, but now subject or ranked under the Father).