Reconciliation (theologically) is the act of God whereby He replaces the state of enmity between God and man with a relationship of friendship through peace purchased by the death of Christ on the cross, which now places the believing sinner in a favorable position with God through the covering of the guilt of sin with Jesus' blood. 

Before we are saved, whether we like it or not, we are the enemies of God. And yet, God in His love, grace, and mercy, made the first move toward unbelieving sinners and died on the cross for us. Because Jesus shed His blood on Calvary, we can now be reconciled to God through faith and placed in a relationship where God's peace is upon us instead of His wrath.