“Conduct yourselves honorably among the Gentiles, so that in a case where they speak against you as those who do what is evil, they will, by observing your good works, glorify God on the day of visitation” (1 Peter 2:12 HCSB).
If the Apostle’s Peter’s counsel from this passage sounds familiar, then it may relate to the fact that he heard a similar message from Jesus in His Sermon on the Mount…
“You are the light of the world. A city set on a hill cannot be hidden. Nor do people light a lamp and put it under a basket, but on a stand, and it gives light to all in the house. In the same way, let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven” (Matthew 5:14-16 ESV).
Much like today, the members of the original audience for this epistle lived among those who were disinclined to accept the message of salvation through Christ. Some of those individuals may have acted to spread rumors, distortions, or deliberate misinformation to help obscure that message. The remedy to those efforts was (and is) a God-honoring lifestyle that undercuts and neutralizes such things, at least among those who will accept the truth.
Ultimately, those who follow this counsel will find vindication “on the day of visitation.” There are several ways in which we might understand this reference. For instance, this phrase might to refer to the time when God inspects our lives and works at the final judgment. When that moment comes, any attempt to present an alternative to the truth regarding our conduct will dissipate. Only the reality of our efforts to honor God with our choices will remain.
Another possibility might involve any life circumstance where God elects to intervene on our behalf. One such intervention took place in the lives of Jacob, the great Old Testament patriarch, and his devious father-in-law Laban (Genesis 31:22-24). Laban’s malicious intent towards Jacob quickly changed when God appeared to him in a dream. That served to constrain Laban and prevent him from escaping his obligation to acknowledge and honor God’s will.
One source builds upon this idea with the following observation…
“[This denotes] a time when God intervenes directly in human affairs, either for blessing (Luk_1:68; Luk_1:78; Luk_7:16; Luk_19:44) or for judgment (Isa_10:3; Jer_6:15). This phrase may be a quotation from Isa_10:3, in which case judgment is in view here. But blessing seems to be the point, since part of the motive for good behavior is winning the non-Christian over to the faith (as in 1Pe_3:1; also apparently in 1Pe_3:15; cf. Mat_5:16).” (1)
(1) NET Bible notes on 1 Peter 2:12 https://classic.net.bible.org/bible.php?book=1Pet&chapter=2&mode=print