Albert Barnes Commentary 1 John 5:18

"We know that whosoever is begotten of God sinneth not; but he that was begotten of God keepeth himself, and the evil one toucheth him not." — 1 John 5:18 (ASV)

We know that whoever is born of God does not sin. This means that such a person is not habitually and characteristically a sinner; they do not ultimately and finally sin and perish. Therefore, they cannot commit the unpardonable sin.

Although a true Christian may fall into sin and grieve fellow believers, we are never to cease praying for them. We are never to feel that they have committed the sin that has no forgiveness, or that they have thrown themselves beyond the reach of our prayers.

This passage, in its connection, is a full proof that a true Christian will never commit the unpardonable sin, and therefore, is a proof that they will never fall from grace. (Compare Hebrews 6:4 and following; Hebrews 10:26).

On the meaning of the assertion made here, that whoever is born of God does not sin, see 1 John 3:6 and following.

Keeps himself. It is not said that he does this by his own strength; rather, he will put forth his best efforts to keep himself from sin, and by divine assistance, he will be able to accomplish it. (Compare 1 John 3:3; Jude 1:21).

And that wicked one does not touch him. The great enemy of all good is repelled in his assaults, and he is kept from falling into his snares.

The word touches (Greek: aptetai) is used here in the sense of harm or injure.

Consider the terms "begotten" and "born," and the phrase "keeps himself." .