John Gill Commentary Ezekiel 44:21

"Neither shall any of the priests drink wine, when they enter into the inner court." — Ezekiel 44:21 (ASV)

Neither shall any priest drink wine
That is, to excess, immoderately, so as to be inebriated with it, (Leviticus 10:9–11) , should not be given to it, and greedy of it, and drink it so as to disguise themselves: this is reckoned among the qualifications of a Gospel minister, (1 Timothy 3:3) , otherwise it is not forbidden good men, or ministers of the word, to drink wine, for health's sake, and for the refreshment of nature, provided it is done in moderation, (1 Timothy 5:23) .

And particularly care should be taken that they drink it in such a manner, when they enter into the inner court :
to attend divine service, since immoderate drinking affects the memory; and such may forget the law and doctrines of the Lord they are to deliver or hear; and may put them upon saying and doing that which is improper and indecent:

Drunkenness in any Christian professor is abominable, especially in a minister of the word; and when it appears in his ministration, it is scandalous to the last degree.