Vs 12 is in contrast to vs 11; those at emnity with the righteous.

Those who belong to the Lord – Born Again Believers (because none are righteous apart from Jesus’ sacrificial blood) who God , Himself, declares righteous, shall flourish and grow.

Our church family encourages each other in hope (not a doubtful-wishing kind of hope, but a ‘now we have hope’ hope) of the promise that one day the devil and his agents that worked so ruthlessly and tirelessly against our goals will be put down and we will see it! The word shall indicates a promise, and you can mark it down – God did!