[KSA]

though ye know them, and be established in the present truth; for those that know the most, know but in part; and may have their knowledge increased; and those that are the most established in the truths of the Gospel, may be confirmed yet more and more. This the apostle mentions as an apology for himself, and to prevent an objection that might be made, as if he had suggested that they were ignorant and unstable; or which might insinuate that there was no necessity of such frequent putting in remembrance; since they were both knowing and stable: by "the present truth" may be meant, either the whole scheme of the Gospel, which was now come by Christ, in opposition to the exhibition of it under the former dispensation, by promise and type; and it being so called, shows that it is always now, and new; that there will be no alteration in it, nor addition to it, it being like the author of it, the same yesterday, today, and for ever, and will not give place to another scheme of things; or else the particular truth of the coming of Christ, either to take vengeance on the Jewish nation, or to judge the world in righteousness, and introduce his own people into the new heavens, and new earth, 2Pe 3:1.

Taken from the commentaries of John Gill