2 Corinthians 5:14
"For Christ's love compels us..."
The old covenant is compelled by fear and obligation because the law demands our perfect behavior. It holds us by the throat with threats and taunts, 'If you don't keep me, you'll go down to the grave and never come up.' The law is a prison.
In new covenant, Jesus satisfies the demands of the law, and therefore there is no need for a prison! The prisoners are set free. Now we are compelled (not by fear and obligation) but by love. The love we have for the one who set us free.
It takes time for that love and appreciation to grow. But as our understanding of Christ's love becomes deeper, higher, richer and fuller; our love FOR HIM bursts out of a thankful heart and here's the best bit - We start living FOR HIM because we are IN LOVE with Him.
Old Covenant = The promise of being PUNISHED means we HAVE to 'get it right'.
New Covenant = The promise of being LOVED means we WANT to 'get it right'.