And let those be first tried He wishes that they who are chosen should not be unknown, but that their integrity should be ascertained, like that of the bishops. And hence it is evident, that they are called blameless who are not stained by any marked vice. Besides, this trial is not for a single hour, but consists in long experience. In a word, when deacons are to be ordained, the choice must not fall at random, and without selection, on any that come to hand, but those men are to be chosen who are approved by their past life in such a manner that, after what may be called full inquiry, they are ascertained to be well qualified.

And let these also first be proved - That is, tried or tested in regard to the things which were the proper qualifications for the office. This does not mean that they were to be employed as "preachers," but that they were to undergo a proper trial in regard to their fitness for the office which they were to fill. They were not to be put into it without any opportunity of knowing what they were. It should be ascertained that they were grave, serious, temperate, trustworthy men; men who were sound in the faith, and who would not dishonor the office. It is not said here that there should be a "formal" trial, as if they were candidates for this office; but the meaning is, that they should have had an opportunity of making their character known, and should have gained such respect for their piety, and their other qualifications, that there would be reason to believe that they would perform the functions of the office well. Thus, in Acts 6:3, when deacons were first appointed, the church was directed to "look out seven men of honest report," who might be appointed to the office.
Then let them use the office of a deacon - Let them be appointed to this office, and fulfil its duties.
Being found blameless - If nothing can be alleged against their character see the notes on 1-Timothy 3:2.

Let these - be proved - Let them not be young converts, or persons lately brought to the knowledge of the truth. This is the same in spirit with what is required of the bishops, 1-Timothy 3:6.
Let no man be put into an office in the Church till he has given full proof of his sincerity and steadiness, by having been for a considerable time a consistent private member of the Church.
Being found blameless - Ανεγκλητοι οντες· Being irreproachable; persons against whom no evil can be proved. The same as in 1-Timothy 3:2, though a different word is used. See the note on 1-Timothy 3:2.

And let these also first be proved,.... Not that they should be tried in any part of the deacon's office, to see how capable they are of performing it; but their internal and external characters are to be looked into and examined, and if they appear, to be right, then they are to be approved of, chosen and called unto, and invested with the office:
then let them use the office of a deacon; let them be employed and minister in the several parts and branches of that office:
being found blameless; not without sin, but free from any gross and enormous one; not before God, but in the sight of men; See Gill on 1-Timothy 3:2.

"And moreover," &c. [ALFORD].
be proved--not by a period of probation, but by a searching inquiry, conducted by Timothy, the ordaining president (1-Timothy 5:22), whether they be "blameless"; then when found so, "let them act as deacons."
blameless--Greek, "unexceptionable"; as the result of public investigation unaccused [TITTMANN].

Let these he proved first - Let a trial be made how they believe. Then let them minister - Let them be fixed in that office.