NET
21 Now David had been thinking, “In vain I guarded everything that belonged to this man in the wilderness. I didn’t take anything from him. But he has repaid my good with evil.
Darby
21 Now David had said, Surely, in vain have I kept all that this [man] had in the wilderness, so that nothing was missed of all that was his; and he has requited me evil for good.
KJV
21 Now David had said, Surely in vain have I kept all that this [fellow] hath in the wilderness, so that nothing was missed of all that [pertained] unto him: and he hath requited me evil for good.