knowing this first of all, that scoffers will come in the last days with scoffing, following their own sinful desires.
3. Knowing this first. The participle knowing may be applied to the Apostle, and in this way, “I labor to stir you up for this reason, because I know what and how great is your impending danger from scoffers.” I however prefer this explanation, that the participle is used in place of a verb, as though he had said, “Know ye this especially.” For it...
To quicken and excite us to a serious minding and firm adhering to what God has revealed to us by the prophets and apostles, we are told that there will be scoffers, men who will make a mock of sin, and of salvation from it. God's way of saving sinners by Jesus Christ is what men will scoff at, and that in the last days, under the gospel.
Commenting on 2 Peter 3:3-7
Knowing this first,.... In the first place, principally, and chiefly, and which might easily be known and observed from the writings of the apostles and prophets; see Ti1 4:1; that there shall come in the last days scoffers, or "mockers"; such as would make a mock at sin, make light of it, plead for it, openly commit it, and glory in it; and scoff at...