Luke 15:22-24

Luke 15:22-24. But the father said to his servants, Bring forth the best robe, and put it on him; and put a ring on his hand, and shoes on his feet: and bring hither the fatted calf, and kill it; and let us eat, and be merry: for this my son was dead, and is alive again; he was lost, and is found. And they began to be merry.

I have never read that they left off being merry, for the conversion of a soul is enough to make eternal joy in the hearts of the righteous.