I've been struck, in my musings on the return of Christ this week, by the great need to constantly connect the doctrine of Christ's return to the doctrine of the cross, and vice versa. If we see Christ's return without the cross we may well tend to legalism. We will emphasize the final judgment and assessment of our lives and the need to live well. The danger is that we will basically become Islamic in our understanding of the final day - it will all be about living a good life. We need to know the grace of the cross to look hopefully to Jesus's return. Further, the cross also tells us Who is coming back. The One who has gone away is the Lord Jesus, my crucified Saviour. He is one who is coming back to judge and rule the world.
On the other hand, we must also view the cross in light of the return of Christ. As I've posted below, we must see that the cross is stepping stone to a new creation. It is the means to the end - and the end is the return of Christ. If I don't have the return of Christ, I will essentially be living 'forgiven' for this life and this world. The cross will lose any sense of hope and will tend to become individualized and spiritualized in its implications for my life.
So: we need both - the crucified Christ and the returning King - to live properly and relate properly to the future.