John Gill Commentary 2 Kings 5:20

"But Gehazi the servant of Elisha the man of God, said, Behold, my master hath spared this Naaman the Syrian, in not receiving at his hands that which he brought: as Jehovah liveth, I will run after him, and take somewhat of him." — 2 Kings 5:20 (ASV)

But Gehazi the servant of Elisha the man of God said
Within himself, observing what had passed:

behold, my master has spared Naaman this Syrian, in not receiving at
his hands that which he brought :
he speaks contemptibly of Naaman, as an alien from the commonwealth of Israel, and reproaches his master for letting him go free, without paying for his cure; when he thought he should have taken what he brought and offered, and given it to needy Israelites, and especially to the sons of the prophets, that wanted it; and perhaps it mostly disturbed him, that he had no share of it himself:

but, as the Lord liveth, I will run after him, and take somewhat of
him ;
the word for "somewhat", wanting a letter usually in it, is what is sometimes used for a blot; and Jarchi observes, that Gehazi taking something from Naaman, was a blot unto him, and indeed such an one that he could not wipe off.