David had just said, "It's been useless – all my watching over this fellow's property in the wilderness so that nothing of his was missing. He has paid me back evil for good."
NIV
Now David had said, Surely in vain have I protected all that this fellow has in the wilderness, so that nothing was missed of all that belonged to him; and he has repaid me evil for good.
AMP
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.
KJV