1 Peter 5:5

Having settled and explained the duty of the pastors or spiritual guides of the church, the apostle comes now to instruct the flock, I. How to behave themselves to their ministers and to one another. He calls them the younger, as being generally younger than their grave pastors, and to put them in mind of their inferiority, the term younger being used by our Saviour to signify an inferior, Luk 22:26. He exhorts those that are younger and inferior to submit themselves to the elder, to give due respect and reverence to their persons, and to yield to their admonitions, reproof, and authority, enjoining and commanding what the word of God requires, Heb 13:17. As to one another, the rule is that they should all be subject one to another, so far as to receive the reproofs and counsels one of another, and be ready to bear one another's burdens, and perform all the offices of friendship and charity one to another; and particular persons should submit to the directions of the whole society, Eph 5:21.; Jam 5:16. These duties of submission to superiors in age or office, and subjection to one another, being contrary to the proud nature and selfish interests of men, he advises them to be clothed with humility.

— Matthew Henry's Concise Commentary (public domain)

ye younger--The deacons were originally the younger men, the presbyters older; but subsequently as presbyter expressed the office of Church ruler or teacher, so Greek "neoteros" means not (as literally) young men in age, but subordinate ministers and servants of the Church. So Christ uses the term "younger." For He explains it by "he that doth serve," literally, "he that ministereth as a deacon"; just as He explains "the greatness" by "he that is chief," literally, "he that ruleth," the very word applied to the bishops or presbyters. So "the young men" are undoubtedly the deacons of the Church of Jerusalem, of whom, as being all Hebrews, the Hellenistic Christians subsequently complained as neglecting their Grecian widows, whence arose the appointment of the seven others, Hellenistic deacons. So here, Peter, having exhorted the presbyters, or elders, not to lord it over those committed to them, adds, Likewise ye neoters or younger, that is, subordinate ministers and deacons, submit cheerfully to the command of the elders [MOSHEIM]. There is no Scripture sanction for "younger" meaning laymen in general (as ALFORD explains): its use in this sense is probably of later date. The "all of you" that follows, refers to the congregation generally; and it is likely that, like Paul, Peter should notice, previous to the general congregation, the subordinate ministers as well as the presbyters, writing as he did to the same region (Ephesus), and to confirm the teaching of the apostle of the Gentiles.

— Jamieson-Fausset-Brown Commentary (public domain)