The height of injustice is receiving the mercy of God and not extending it to others.
To get a brand new start, to be lovingly reminded that we are first class citizens in the kingdom of God, to be affirmed we are his sons and daughters, to be crowned and blessed with additional grace, to receive all of that probably all within a 24 hour period, and NOT extend it to others- that is an unjustice in God’s eyes.
And this will be tested in all of our relationships.