if ye have heard him and been instructed in him according as the truth is in Jesus;

if so be ye did hear him, and in him were taught, as truth is in Jesus;

if at least you have heard His voice and in Him have been taught - and this is true Christian teaching -

If in fact you gave ear to him, and were given teaching in him, even as what is true is made clear in Jesus:

For certainly, you have listened to him, and you have been instructed in him, according to the truth that is in Jesus:

and through union with him were taught the truth, as it is to be found in Jesus.

Si quidem ipsum audistis, et in ipso estis edocti, quemadmodum est veritas in Iesu;

If ye have heard him. To excite their attention and earnestness the more, he not only tells them that they had heard Christ, but employs a still stronger expression, ye have been taught in him, as if he had said, that this doctrine had not been slightly pointed out, but faithfully delivered and explained. As the truth is in Jesus. This contains a reproof of that superficial knowledge of the gospel, by which many are elated, who are wholly unacquainted with newness of life. They think that they are exceedingly wise, but the apostle pronounces it to be a false and mistaken opinion. There is a twofold knowledge of Christ, -- one, which is true and genuine, -- and another, which is counterfeit and spurious. Not that, strictly speaking, there are two kinds; but most men falsely imagine that they know Christ, while they know nothing but what is carnal. In another Epistle he says, "If any man be in Christ, let him be a new creature." (2-Corinthians 5:17.) So here he affirms that any knowledge of Christ, which is not accompanied by mortification of the flesh, is not true and sincere.

If so be that ye have heard him - If you have listened attentively to his instructions, and learned the true nature of his religion. There may be a slight and delicate doubt implied here whether they had attentively listened to his instructions. Doddridge, however, renders it, "Seeing ye have heard him;" compare notes on Ephesians 3:2.
And have been taught by him - By his Spirit, or by the ministers whom he had appointed.
As the truth is in Jesus - If you have learned the true nature of his religion as he himself taught it. What the truth was which the Lord Jesus taught, or what his principles implied, the apostle proceeds to state in the following verses.

If so be that ye have heard him - Ειγε, Seeing that, since indeed, ye have heard us proclaim his eternal truth; we have delivered it to you as we received it from Jesus.

If so be that ye have heard him, and have been taught by him, (d) as the truth is in Jesus:
(d) As they have learned who acknowledge Christ indeed, and in good earnest.

If so be that ye have heard him,.... Not heard him preach, but heard him preached; and that not merely externally, with the outward hearing of the ear; though oftentimes spiritual conviction and illumination, true faith in Christ, real comfort from him, and establishment and assurance of interest in him, come this way, as to these Ephesians, Ephesians 1:13 but internally, so as to know him, understand his word, and distinguish his voice; so as to approve of him and love him, and believe in him; feel the power of his Gospel, relish his truths, and obey his ordinances, and so bring forth fruit to his glory; as such do, who are quickened by him, whose ears are unstopped, and their hearts opened, and their understandings enlightened; and who have hearing ears, and understanding hearts given them:
and have been taught by him: not personally, but by his Spirit and ministers; for Christ is not only the subject of the ministry of the word, and whom the Spirit of God teaches and directs souls to for righteousness, pardon, cleansing, and for every supply of grace; but he is the efficient cause of teaching; and there is none who teaches like him: and those who are taught by him, are taught
as the truth is in Jesus; as the Gospel is in him, as in its original and subject; for he is truth itself, and grace and truth came by him; and as it was preached by him, and so is pure and unmixed.

If so be that--not implying doubt; assuming what I have no reason to doubt, that
heard him--The "Him" is emphatic: "heard Himself," not merely heard about Him.
taught by him--Greek, "taught IN HIM," that is, being in vital union with Him (Romans 16:7).
as the truth is in Jesus--Translate in connection with "taught"; "And in Him have been taught, according as is truth in Jesus." There is no article in the Greek. "Truth" is therefore used in the most comprehensive sense, truth in its essence, and highest perfection, in Jesus; "if according as it is thus in Him, ye have been so taught in Him"; in contrast to "the vanity of mind of the Gentiles" (Ephesians 4:17; compare John 1:14, John 1:17; John 18:37). Contrast John 8:44.

Seeing ye have heard him - Teaching you inwardly by his Spirit. As the truth is in Jesus - According to his own gospel.