With this phrase Peter makes it clear that the heretics have come from within the church and not from outside of it. They deny the sovereign Lord (Master) who bought them. Those redeemed by Christ belong to him (1 Corinthians 15:23; Galatians 5:24) but the heretics have repudiated the very one who freed them, the Master.1 They owed Christ obedience but have failed to submit to him.2 They are apostate Christians.3 Since they deny Christ and refuse to submit to him, they will face judgment when Christ denies them before his Father (Matthew 10:33). If there is no repentance, then judgment and destruction is what waits for them—the very judgment which they deny (2 Peter 3:4).4 (The fact that this judgment comes soon undermines the claim made by some scholars that the letter was written in the early catholic period when the hope of Christ’s immediate return had faded from view.)5
1 But false prophets also arose among the people, just as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Master who bought them, bringing upon themselves swift destruction.