Shared ground
Peter presents these lines as a reminder, not a fresh set of ideas. He says this is his second letter to the same people, and in both letters he has had the same aim: to “stir up” their thinking by bringing earlier teaching back to mind. That makes remembering a central theme of the chapter’s opening.
The content to be remembered has two streams: (1) “words spoken before by the holy prophets,” and (2) “the commandment” delivered through “the apostles of the Lord and Savior.” Explicitly in the text, Peter treats both as recognized, authoritative sources that should shape how the community evaluates what it hears next.
Where interpretation differs (only where needed)
What does “second letter” mean? Some read it as a straightforward reference to a previous letter from Peter to these same readers (most naturally 1 Peter). Others think it could refer to an earlier letter we no longer have, since the phrase itself does not name the first letter.
Who are the “holy prophets”? Many take this as the prophets of Israel whose words are preserved in Scripture. Others think the wording could be broader, including prophetic voices recognized in the early Christian movement, though the “spoken before” language often fits earlier Scripture.
What is the “commandment”? Some understand a single core command (often summarized as Christ’s teaching) that the apostles delivered. Others understand it as a collection of apostolic instructions (a body of teaching), since a singular noun can function that way.
Why the disagreement exists
The passage is brief and assumes shared knowledge between writer and readers. It does not specify the earlier letter, does not define “prophets,” and uses a singular “commandment” that can be read either as one key charge or as a summary label for more teaching.
What this passage clearly contributes
Peter frames apostolic writing as a means of preserving continuity: his goal is to keep readers thinking clearly and honestly by recollection. He also places apostolic instruction alongside prophetic words as the primary “already given” standard. These verses set up the rest of the chapter by signaling that what follows should be tested against prior, established teaching rather than novelty.