According to Romans 14:7-9, not one of us--us being Christians, professing Christians who have a penitent faith in Christ--lives for himself, and not one of us dies for himself. Those without a penitent faith in Christ do live for themselves, or they live for an idol or idols, but such cannot die for themselves, for they cannot save themselves. Christians live for the Lord. Everything we do, we filter through the lens of God's will. Christians die for the Lord, we die to preserve his holy name, and we die satisfied that we are his, and that to die is not eternal death but the start of an eternal life in which we know God forever. So, there is no living for the Lord with the idea that our relationship with the Lord ends at death. We are the Lord's in both life and death. And we aren't just living for the Lord in order to achieve some kind of benefit after death. We love the Lord, and our relationship with him begins in life and that same relationship continues into death and life after death. The Lord owns us now, and he will continue to own us forever. Otherwise, why are you willing to be the Lord's if not forever?
This is the reason for the resurrection. Christ is Lord. He is Lord of the living and the dead. His resurrection showed us--irrefutably--that death was not the end. He rose again from the dead to show us that we, too, will rise from the dead. That all who have faith in him will rise from the dead. When we have faith in him, it means that he owns us. We are Christ's and he owns us, because he paid for us with his blood. We cannot buy ourselves back, because we cannot afford it, and why would we want to buy ourselves back? Being owned by Christ is the ultimate state of being. God put the Christ--the messiah--in place to be our Lord and Savior, to not only save our souls from destruction but to be our Lord and Master, sanctifying us by his Spirit, and changing us into his likeness. Only a Lord and Master has the authority to do that with those whom he owns.
In John 20, the gentiles begin to seek Jesus, and he knows that the time has come for his death and resurrection. All the world needed to see what eternal life looked like, even though many would--and still do--reject the offer. Jesus told his disciples that anyone who does not die to himself is isolated from God. This is hell--eternity without God. However, if we die to ourselves, if we give up all the pleasures of worldly living and begin to live for God, we will bear much fruit for the Lord, fruit that carries over into the next life. Jesus said, "he who loves his life loses it, and he who hates his life in this world will keep it to life eternal." Since Christ owns us, we must serve him, and that means following him: living for him and following his path. We are talking about a literal following of him, so that where he is, there we be also. This is not a head-only acknowledgement of Christ's Lordship. He is our master, and so where he tells us to go, we go, and that means following him to the grave. We die to ourselves. No man can serve two masters. Only master Jesus is possible. The result is the Father honoring that servant with everlasting life.
Are you living for Christ? Are you ready to die for Christ? Are you following Christ's rule? Are you being a citizen of his kingdom by obeying his every command? Are you bearing his fruit? Have you killed the worldly life in you? Have you disowned all but Christ? Are you serving him and him alone?