Matthew Henry on 2 Samuel 8:15-18

David neither did wrong, nor denied or delayed right to any. This speaks his close application to business; also his readiness to admit all addresses and appeals made to him. He had no respect of persons in judgment. Herein he was a type of Christ. To Him let us submit, his friendship let us seek, his service let us count our pleasure, diligently attending to the work he assigns to each of us. David made his sons chief rulers; but all believers, Christ's spiritual seed, are better preferred, for they are made kings and priests to our God, Re 1:6.