Adam Clarke on 2 Kings 5:10

Sent a messenger - Did not come out to speak with him: he had got his orders from God, and he transmitted them to Naaman by his servant.

Wash in Jordan seven times - The waters of Jordan had no tendency to remove this disorder but God chose to make them the means by which he would convey his healing power. He who is the author of life, health, and salvation, has a right to dispense, convey, and maintain them, by whatsoever means he pleases.