Adam Clarke on Luke 4:27

None of them was cleansed - This verse is to be understood as the 26th; for Naaman, being a Syrian, was no leper in Israel. The meaning of these verses is, God dispenses his benefits when, where, and to whom he pleases. No person can complain of his conduct in these respects, because no person deserves any good from his hand. God never punishes any but those who deserve it; but he blesses incessantly those who deserve it not. The reason is evident: justice depends on certain rules; but beneficence is free. Beneficence can bless both the good and the evil; justice can punish the latter only. Those who do not make this distinction must have a very confused notion of the conduct of Divine Providence among men.