2 Petrus 2:21

2:21 For it would have been better for them never to have known the way of righteousness than, having known it, to turn back from the holy commandment that had been delivered to them.

2 Petrus 3:2

3:2 I want you to recall ¹  both ²  the predictions ³  foretold by the holy prophets and the commandment of the Lord and Savior through your apostles. ⁴ 

[3:2]  ¹ tn Grk “to remember.” “I want you” is supplied to smooth out the English. The Greek infinitive is subordinate to the previous clause.

[3:2]  ² tn “Both” is not in Greek; it is supplied to show more clearly that there are two objects of the infinitive “to remember” – predictions and commandment.

[3:2]  ³ tn Grk “words.” In conjunction with πρόειπον (proeipon), however, the meaning of the construction is that the prophets uttered prophecies.

[3:2]  ⁴ sn Holy prophets…apostles. The first chapter demonstrated that the OT prophets were trustworthy guides (1:19-21) and that the NT apostles were also authoritative (1:16-18). Now, using the same catch phrase found in the Greek text of 1:20 (τοῦτο πρῶτον γινώσκοντες, touto prwton ginwskontes), Peter points to specific prophecies of the prophets as an argument against the false teachers.