I John 2:20

But--Greek, "And." He here states the means which they as believers have wherewith to withstand. Antichrists (Jo1 2:18), namely, the chrism (so the Greek: a play upon similar sounds), or "anointing unguent," namely, the Holy Spirit (more plainly mentioned further on, as in John's style, Jo1 3:24; Jo1 4:13; Jo1 5:6), which they ("ye" is emphatical in contrast to those apostates, Jo1 2:19) have "from the Holy One, Christ" (Joh 1:33; Joh 3:34; Joh 15:26; Joh 16:14): "the righteous" (Jo1 2:1), "pure" (Jo1 3:3), "the Holy One" (Act 3:14) "of God"; Mar 1:24. Those anointed of God in Christ alone can resist those anointed with the spirit of Satan, Antichrists, who would sever them from the Father and from the Son. Believers have the anointing Spirit from the Father also, as well as from the Son; even as the Son is anointed therewith by the Father. Hence the Spirit is the token that we are in the Father and in the Son; without it a man is none of Christ. The material unguent of costliest ingredients, poured on the head of priests and kings, typified this spiritual unguent, derived from Christ, the Head, to us, His members. We can have no share in Him as Jesus, except we become truly Christians, and so be in Him as Christ, anointed with that unction from the Holy One. The Spirit poured on Christ, the Head, is by Him diffused through all the members. "It appears that we all are the body of Christ, because we all are anointed: and we all in Him are both Christ's and Christ, because in some measure the whole Christ is Head and body." and--therefore. ye know all things--needful for acting aright against Antichrist's seductions, and for Christian life and godliness. In the same measure as one hath the Spirit, in that measure (no more and no less) he knows all these things.

Here, I. The apostle encourages the disciples (to whom he writes) in these dangerous times, in this hour of seducers; he encourages them in the assurance of their stability in this day of apostasy: But you have an unction from the Holy One, and you know all things. We see, 1. The blessing wherewith they were enriched - an unguent from heaven: You have an unction. True Christians are anointed ones, their name intimates as much. They are anointed with the oil of grace, with gifts and spiritual endowments, by the Spirit of grace. They are anointed into a similitude of their Lord's offices, as subordinate prophets, priests, and kings, unto God. The Holy Spirit is compared to oil, as well as to fire and water; and the communication of his salvific grace is our anointing. 2. From whom this blessing comes - from the Holy One, either from the Holy Ghost or from the Lord Christ, as Rev 3:7, These things saith he that is holy - the Holy One. The Lord Christ is glorious in his holiness. The Lord Christ disposes of the graces of the divine Spirit, and he anoints the disciples to make them like himself, and to secure them in his interest. 3. The effect of this unction - it is a spiritual eye-salve; it enlightens and strengthens the eyes of the understanding: "And thereby you know all things (Jo1 2:20), all these things concerning Christ and his religion; it was promised and given you for that end," Joh 14:26. The Lord Christ does not deal alike by all his professed disciples; some are more anointed than others. There is great danger lest those that are not thus anointed should be so far from being true to Christ that they should, on the contrary, turn antichrists, and prove adversaries to Christ's person, and kingdom, and glory. II. The apostle indicates to them the mind and meaning…

2:20-23 for the Holy One has given you his Spirit: The Holy Spirit gives believers the ability to understand and recognize spiritual truth (see Isa 61:1; Acts 10:38; 2 Cor 1:21-22). Those who have the Spirit know the truth about the Father and the Son and can detect what does not accord with the truth of the apostles’ teaching.