There is an interesting story that begins in Acts 13.
God tells the church to commission and send out Barnabas and Paul to other cities, telling the people they meet about Jesus. They do this, taking with them John (also called, John Mark or just Mark).
The thing is, God didn’t tell them to take John Mark; he apparently doesn’t belong there. This is borne out later, when John Mark deserts Barnabas and Paul to return home.
Later, Barnabas wants to give John Mark a second chance (an example of mercy), but Paul says “no” (an example of justice). They part company over this disagreement, each going their separate ways. This might seem like a bad thing, but it turns out to be a good thing, as they are then able to cover twice the ground, doubling their effectiveness and outreach.
For John Mark, his story ends on a positive note, too, with him and Paul later being reconciled (an example of grace) and Paul esteeming John Mark as his fellow worker and as being useful to him.
This is a great lesson in life. Despite making mistakes along the way, we can still finish well. John Mark did and so can we.