What does 2 Samuel 19:24 mean?

Mephibosheth, Saul’s grandson, also came down to meet the king. He hadn’t taken care of his feet, trimmed his beard, or washed his clothes since the king left, showing how much he was grieving. 2 Samuel 19:24 - Modern Text Bible

(Mephibosheth’s appearance shows he’s been mourning David’s absence, not plotting against him.)