Warning against Deliberate Sin
26 For if we deliberately sin after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, 27 but a terrifying expectation of judgment and the fury of a fire about to consume the adversaries. 28 If anyone disregards Moses’ law, he dies without mercy, based on the testimony of two or three witnesses. 29 How much worse punishment do you think one will deserve who has trampled on the Son of God, regarded as profane[d] the blood of the covenant by which he was sanctified, and insulted the Spirit of grace? 30 For we know the One who has said, Vengeance belongs to Me, I will repay,[e][f] and again, The Lord will judge His people.[g] 31 It is a terrifying thing to fall into the hands of the living God!
32 Remember the earlier days when, after you had been enlightened, you endured a hard struggle with sufferings. 33 Sometimes you were publicly exposed to taunts and afflictions, and at other times you were companions of those who were treated that way. 34 For you sympathized with the prisoners[h] and accepted with joy the confiscation of your possessions, knowing that you yourselves have a better and enduring possession.[i] 35So don’t throw away your confidence, which has a great reward. 36 For you need endurance, so that after you have done God’s will, you may receive what was promised.
37 For yet in a very little while,
the Coming One will come and not delay.
38 But My righteous one[j] will live by faith;
and if he draws back,
I have no pleasure in him.[k]
39 But we are not those who draw back and are destroyed, but those who have faith and obtain life.
2 Peter 2:21-22Holman Christian Standard Bible (HCSB)
21 For it would have been better for them not to have known the way of righteousness than, after knowing it, to turn back from the holy command delivered to them. 22 It has happened to them according to the true proverb: A dog returns to its own vomit,[a] and, “a sow, after washing itself, wallows in the mud.”
Its really not that scary. The author is just saying remain in Faith. Well, I suppose for people that are living lukewarm this verse won't sit too well on the stomach.
Obviously, this verse is similar to......
Oops, that’s “if” the case which a deliberate sinning would take impossible for a real saved but these speaks of the adversaries, false teachers which does that and as it is expected for them a punishment in the fury of fire. Nothing is said for real saved to fall away. This seem drawing back of the believers is nothing about losing one’s salvation though if one drawback God has no pleasure in him but not the writer is talking of losing salvation.