Malachi 2:7

“For the priest’s lips should keep knowledge, etc.] Or “shall keep knowledge”, as the Septuagint and Vulgate Latin versions; or “do keep knowledge”, as the Arabic version; and so the Syriac version, “for the lips of the priest drop knowledge”; all this is true of Christ our great High Priest; for as it was predicted of him, that his lips should keep knowledge, so they have kept it, and do keep it; not concealing it, but preserving it, and communicating it freely and openly; as he did to his disciples and followers when here on earth, and by them to others; and still does by his Spirit, giving to men the knowledge of themselves and state; the knowledge of himself, and the way of salvation by…”

“In doing so (Mal 2:6) he did his duty as a priest, "for," &c. knowledge--of the law, its doctrines, and positive and negative precepts (Lev 10:10-11; Deu 24:8; Jer 18:18; Hag 2:11). the law--that is, its true sense. messenger of . . . Lord--the interpreter of His will; compare as to the prophets, Hag 1:13. So ministers are called "ambassadors of Christ" (Co2 5:20); and the bishops of the seven churches in Revelation, "angels" or messengers (Rev 2:1, Rev 2:8, Rev 2:12, Rev 2:18; Rev 3:1, Rev 3:7, Rev 3:14; compare Gal 4:14).”

“For the priest’s lips should keep knowledge - o “He assigns the reason for what he had just said, the law of truth was in his mouth; they had done what it was their duty to do; as in Ecclesiasticus it is said of Aaron (Ecclesiasticus 45:17), ‘God gave unto him His commandments, and authority in the statutes of judgments, that he should teach Jacob the testimonies, and inform Israel in His laws.’ So Paul requires of Titus to ordain such overseers, as shall be able to Titus 1:9, ‘exhort by sound doctrine and to convince gainsayers.’ Wherefore Ambrose calls the Bible, which contains the law of God, ‘the book of priests,’ as specially belonging to them, to be specially studied by them. Jerome…”

“Should keep knowledge - It is this that their office binds them to; it is the duty of all God's people to know his law, but the priest's duty to know it more than others. And they - The people. Malachi 2:8”

“2:7 The priests had been entrusted with the sacred knowledge of God as revealed in the law of Moses. Through their role as teachers, they were guardians of God’s covenant with Israel (Deut 33:9-10). • messenger (Hebrew mal’ak): This may be a wordplay on the name Malachi (mal’aki). Usually this title was reserved for Hebrew prophets in the Old Testament, but Malachi ascribes prophetic duties to the priest, since the priests were to interpret God’s word.”

“the priest's: Lev 10:11; Deu 17:8-11, Deu 21:5, Deu 24:8; Ch2 17:8, Ch2 17:9, Ch2 30:22; Ezr 7:10; Neh 8:2-8; Jer 15:19, Jer 18:18; Hag 2:11-13; Ti2 2:24, Ti2 2:25 the messenger: Mal 3:1; Isa 42:19, Isa 44:26; Hag 1:13; Joh 13:20, Joh 20:21; Act 16:17; Co2 5:20; Gal 4:14; Th1 4:8 Malachi 2:8”