'Clean' in the Bible

Elisha sent a messenger to him, saying, "Go, you must wash seven times in the Jordan, then your flesh shall return to you, and you shall be clean."

Are not the Abana and the Pharpar, the rivers of Damascus, better than all of the waters of Israel? Could I not wash in them that I may be clean?" Then he turned and left in anger.

But his servants came near and spoke to him and said, "My father, [if] the prophet had spoken a difficult thing to you to do, would you not have done [it]? [Why not] even when he says to you, 'Wash and you shall be clean'?"

So he went down and plunged into the Jordan seven times, according to the word of the man of God, and his flesh returned as the flesh of a small boy, and he was clean.