"The fact that Jesus is sitting means that his work of redemption is finished... because of Jesus’ one sacrifice we have been perfected for all time. “But don’t I still sin, and don’t I need to change?” Yes! But in God’s sight, because of Jesus’ one sacrifice, you are ‘complete’—not lacking anything. In terms of your relationship with him you are perfect. There is nothing more that needs to be done to reconcile you to God. Nothing more that needs to be done to pay for your sin. Nothing more that needs to be done to deal with his wrath. As Christians we need to continually remind ourselves of the cross, but we also need to remind ourselves of Jesus sitting at the right hand of God, because that reminds us that his death on the cross was effective and that we are now perfect in God’s sight."
Peter Orr, What is Jesus doing now (read the full thing here)