Charles Ellicott Commentary Judges 9:16

"Now therefore, if ye have dealt truly and uprightly, in that ye have made Abimelech king, and if ye have dealt well with Jerubbaal and his house, and have done unto him according to the deserving of his hands" — Judges 9:16 (ASV)

Now therefore. —Here follows the epimuthion, or application of the fable. Judges 9:16–18 are the protasis of the sentence, which is a long and parenthetic series of premises; the conclusion, or apodosis, follows in Judges 9:19.

If you have done truly and sincerely. —A bitterly ironical supposition with a side glance at the phrase used by the bramble .