My question is that since he came back to life, is that really a sacrifice? Isn't he God and he knew that he cannot die?
He did die. Grave yard dead. He didn't partially die. He was DEAD. Fully dead. Jesus was human. He was fully a man. He had a human brain, a cardiovascular system, etc. He had to be cleaned as an infant. He wasn't born potty trained. He had to learn to speak. He wasn't born speaking fluent Hebrew and Greek. And, yes, He was also God. It is a mystery to comprehend. He was God, yet was fully dependent upon God. He didn't have magic powers. He was empowered by God. It was the essence of God working through the real flesh of a man. A prototype I guess you could say, of what is to come. This flesh was in FULL and TOTAL submission to the invisible God. Every breath, every word, every thought and every deed, was completely motivated and sourced by the living God. So when you heard from Jesus, you heard from the voice of God Himself. When His hand reached out, it was the hand of God. Jesus the man, was a glove into which the hand of God was fit. And so God thrust Himself into our reality. Because we good not climb to Him, He descended to us. (Eph 4:9-10)
Yes, it was really a sacrifice. Why? Because of the quality of the One sacrificed. Jesus was the spotless lamb. He was the God/Man.
Wouldn't Jesus' death have more meaning if he never came back to life?
This verse popped into my head immediately upon reading your question.
Paul answers this. 1 Cor 15: 12-19
"But if it is preached that Christ has been raised from the dead, how can some of you say that there is no resurrection of the dead? If there is no resurrection of the dead, then not even Christ has been raised.
And if Christ has not been raised, our preaching is useless and so is your faith. More than that, we are then found to be false witnesses about God, for we have testified about God that he raised Christ from the dead. But he did not raise him if in fact the dead are not raised. For if the dead are not raised, then Christ has not been raised either. And if Christ has not been raised, your faith is futile; you are still in your sins. Then those also who have fallen asleep in Christ are lost. If only for this life we have hope in Christ, we are to be pitied more than all men. "
I can not answer that question any more directly that what the Bible has done for you.
Christ died a REAL physical death.
Also, since he died for everybody, shouldn't everyone (believers and nonbelievers) be going to heaven?
I was told that Jesus died for everyone (both believers and nonbelievers).
If everyone is not going to heaven, then wouldn't his death be in vain, since Christians and believers are going to go to heaven anyways.
Can a person refuse a free gift? Most certainly. I could offer to pay for my child's college education, but I can't make them go to college. I can offer the gift of this education, but they must appropiate the gift by responding to it affirmatively. Salvation is a response to the gift of God and the finished work of Christ on the cross. Thus we are to receive salvation. The quarterback can throw the perfect pass, right on target. But if the receiver does not reach out and grab hold of the ball, then the catch will not be made.
Again, I can't explain it any better than the scriptures. This verse popped into my head as well.
John 1:12 "Yet to all who
received him, to those who believed in his name, he gave the right to become children of God."