In his letter Peter has already used this very word repeatedly (1 Peter 2:13, 1 Peter 2:18; 1 Peter 3:1, 1 Peter 3:5, 1 Peter 3:22). The term means literally to place under
and so to surrender one’s perceived rights or preferences. This means in practice that the group identified as “those who are younger” needs to adopt a mindset of humility even as it (potentially) chafes at the bit to implement its own insights. That posture is part and parcel of recognizing that the flock is “of God” (1 Peter 5:2; “chief shepherd” in 1 Peter 5:4) and he has mandated particular men—the “elders”—to “shepherd” it for him. So the younger need to let themselves be shepherded.
5 Likewise, you who are younger, be subject to the elders. Clothe yourselves, all of you, with humility toward one another, for “God opposes the proud but gives grace to the humble.”