The verse Romans 12:15 at first seems out of place among verses speaking about blessing those that persecute you and not repaying evil for evil. “Rejoice with those who rejoice; mourn with those who mourn.”
But then as you look at v. 16 and the emphasis on caring about others 1st, you see He is saying that life is too short to be consumed with a negative, grudge-filled, “get even” attitude. Rejoice with someone today that is celebrating because life turns on a dime, on the point of a needle and in a moment you could mourning with one who’s life has been turned inside out, changed to never be the same.
There is a season for everything so we all will have opportunities to experience joy and heartbreak. Don’t miss those moments of joy by dwelling on pay-back, revenge and un-forgiveness. Don’t get distracted by the negative today, rejoice as God gives you the opportunity.