Whosoever denieth the Son, the same hath not the Father - That is, has no just views of the Father, and has no evidence of his friendship. It is only by the Son of God that the Father is made known to people, Matthew 11:27; Hebrews 1:2-3, and it is only through him that we can become reconciled to God, and obtain evidence of His favor. See the notes at John 5:23.
But he that acknowledges the Son, hath the Father also - This passage, in the common version of the New Testament, is printed in italics, as if it were not in the original, but was supplied by the translators. It is true that it is not found in all the manuscripts and versions; but it is found in a large number of manuscripts, and in the Vulgate, the Syriac, the Aethiopic, the Coptic, the Armenian, and the Arabic versions, and in the critical editions of Griesbach, Tittmann, and Hahn. It is probable, therefore, that it should be regarded as a genuine portion of the sacred text. It is much in the style of John, and though not necessary to complete the sense, yet it well suits the connection. As it was true that if one denied the Son of God he could have no pretensions to any proper acquaintance with the Father, so it seemed to follow that if anyone had any proper knowledge of the Son of God, and made a suitable confession of him, he had evidence that he was acquainted with the Father. Compare John 17:3; Romans 10:9. Though, therefore, this passage was wanting in many of the manuscripts consulted by the translators of the Bible, and though in printing it in the manner in which they have they showed the great caution with which they acted in admitting anything doubtful into their translation, yet the passage should be restored to the text, and be regarded as a genuine portion of the Word of God. The great truth can never be too clearly stated, or too often inculcated, that it is only by a knowledge of the Lord Jesus Christ that we can have any true acquaintance with God. and that all who have just views of the Saviour are in fact acquainted with the true God, and are heirs of eternal life.

Whosoever denieth the Son - He who denies Jesus to be the Son of God, and consequently the Christ or Messiah, he hath not the Father - he can have no birth from above, he cannot be enrolled among the children of God, because none can be a child of God but by faith in Christ Jesus.
He that acknowledgeth the Son hath the Father also - This clause is printed by our translators in Italics to show it to be of doubtful authority, as it was probably wanting in the chief of those MSS. which they consulted, as it was in Coverdale's Bible, printed 1535; Tindall's Text, printed 1548; and in all the early printed editions (which I have seen) previously to 1566; the Bible of Richard Cardmarden, printed in English at Rouen, where this clause is inserted in a different letter between brackets. But that the clause is genuine, and should be restored to the text without any mark of spuriousness, as I have done in the text of this work, is evident from the authorities by which it is supported. It is found in ABC, and in between twenty and thirty others of the best authority; as also in both the Syriac, Erpen's Arabic, Coptic, Sahidic, Armenian, and Vulgate. It is also quoted as a part of the text by Origen, Meletius, Athanesius, both the Cyrils, Theophylact, Vigilius of Tapsum, Pelagius, Cerealis, Cassian; and in substance by Euthalius, Epiphanius, Cyprian, Hilary, Faustinus, Lucifer of Cagliari, Augustine, and Bede. It is wanting in the Arabic, in the Polyglot, in a MSS. in the Harleian library, and in some few others. It is doubtless genuine, and Griesbach has with propriety restored it to the text, from which it never should have been separated.

(s) Whosoever denieth the Son, the same hath not the Father: [
(but) he that acknowledgeth the Son hath the Father also].
(s) They deceive themselves, and also deceive others, who say that the Moslems and other infidels worship the same God that we do.

Whosoever denieth the Son,.... Jesus Christ to be the true, proper, natural, essential, and eternal Son of God:
the same hath not the Father; or does not hold the Father; or "believe the Father", as the Syriac version renders it; for there cannot be a father without a son; and he that honours not the Son, by owning him as such, honours not the Father; whatever reflects dishonour on the Son, reflects dishonour on the Father. If Christ is not truly and properly the Son of God, the Father is not truly and properly the Father of Christ; if Christ is only a Son in a figurative and metaphorical sense, the Father is only a Father in a figurative and metaphorical sense; if Christ is a Son only by office, then the Father is a Father only by office, which is monstrously stupid. Such an one does not hold the true doctrine of the Father, and does not appear to have true faith in him, true love unto him, or real interest in him, only by profession:
but he that acknowledgeth the Son, hath the Father also: this clause is left out in many copies, and stands as a supplement in our version; but is in the Alexandrian copy, in four of Beza's manuscripts, and in some others; and in the Vulgate Latin, Syriac, and Ethiopic versions; and confirms and illustrates what is before said; for as he that denies the sonship of Christ cannot hold the paternity of God, so he that owns the sonship of Christ, the second Person, maintains the paternity of the first; for these two are correlates, and mutually put, or take away each other: no mention is made of the Spirit, because, as yet, no controversy had risen concerning him.

Greek, "Every one who denieth the Son, hath not the Father either" (1-John 4:2-3): "inasmuch as God hath given Himself to us wholly to be enjoyed in Christ" [CALVIN].
he--that acknowledgeth the Son hath the Father also. These words ought not to be in italics, as though they were not in the original: for the oldest Greek manuscripts have them.
hath--namely, in his abiding possession as his "portion"; by living personal "fellowship."
acknowledgeth--by open confession of Christ.

Whosoever denieth the eternal Son of God, he hath not communion with the Father; but he that truly and believingly acknowledgeth the Son, hath communion with the Father also.