Gombiner utilized his extensive erudition in order to attempt a harmonization between the rulings of Caro and Isserles, though generally preferring the latter when no compromise was possible. His approach was remarkable for its insistance upon the preservation of religious custom, and for its reliance upon Kabbalistic traditions (a policy not normally followed in works on Jewish law).
The title is taken from Malachi 2:7: "for the priest's lips should keep knowledge and they should seek the law at his mouth" and alludes to the author's status as a "Kohen," i.e., his descent from the Hebrew priesthood.
The "ShaKh" (the acronym by which he is generally known) provides extensive discussions and interpretations of the Shulhan 'Arukh and its sources, paying particular attention to the responsa literature and to works that were not utilized by Caro. He made use of the "Me'irat 'Einayim" commentary by Rabbi Joshua Falk, which he often supplements with his own explanations. He also maintained an intense exchange with Rabbi David Hallevi on their many disputed rulings.
His commentary is distinguished by its clear style and its independance of opinion; he frequently finds himself in disagreement with the decisions of Caro, Isserles and Rabbi Moses Lima's "Helkat Mehokek", making allowances for the fact that the latter had not lived to complete or polish his commentary.