What does Romans 5:11 mean?

This verse sums up the passage which began in the first verse of this chapter. Paul adds that, because all he has said leading up to this is true, we can rejoice in God through our Lord Jesus Christ. On top of the fact that we have been justified and will not suffer God's wrath for our sin, we can participate in the celebration of God Himself. After all, we have received reconciliation with God through Christ's death in our place on the cross and our faith in Him.

Reconciliation describes what happens between two people formerly separated by a dispute, when that dispute is resolved and they are able to come back together. God is the one who had the dispute with us, because of our sin. Christ's death and resurrection satisfied God's demands to make things right between us, and, through our faith alone, the dispute is ended. "We," in this context meaning those who have accepted Christ through saving faith, are reconciled.

Notice that this statement is in the past tense. The transaction is complete. Those who have trusted in Christ have now and forever received reconciliation with God. Period. We have peace with Him (Romans 5:1). We stand now in His grace (Romans 5:2). He has poured His love in our hearts (Romans 5:5). All is decided. Since God is the one who made it happen, nobody can take it away. We are not waiting to see if God will be okay with us after we die. Because we are in Christ, we know that God is okay with us right now, and always will be.