Be ye doers of the word. The doer here is not the same as in Romans 2:13, who satisfied the law of God and fulfilled it in every part, but the doer is he who from the heart embraces God's word and testifies by his life that he really believes, according to the saying of Christ, "Blessed are they who hear God's word and keep it," (Luke 11:28;) for he shews by the fruits what that implanting is, before mentioned. We must further observe, that faith with all its works is included by James, yea, faith especially, as it is the chief work which God requires from us. The import of the whole is, that we ought to labor that the word of the Lord should strike root in us, so that it may afterwards fructify. [1]

Footnotes

1 - Calvin takes no notice of the last sentence, "deceiving yourselves." The participle means deceiving by false reasoning.; it may be rendered with Doddridge, "sophistically deceiving yourselves."

But be ye doers of the word, and not hearers only - Obey the gospel, and do not merely listen to it. Compare Matthew 7:21.
Deceiving your own selves - It is implied here, that by merely hearing the word but not doing it, they would deceive their own souls. The nature of this deception was this, that they would imagine that that was all which was required, whereas the main thing was that they should be obedient. If a man supposes that by a mere punctual attendance on preaching, or a respectful attention to it, he has done all that is required of him, he is laboring under a most gross self-deception. And yet there are multitudes who seem to imagine that they have done all that is demanded of them when they have heard attentively the word preached. Of its influence on their lives, and its claims to obedience, they are utterly regardless.

But be ye doers of the word - They had heard this doctrine; they had believed it; but they had put it to no practical use. They were downright Antinomians, who put a sort of stupid, inactive faith in the place of all moral righteousness. This is sufficiently evident from the second chapter.
Deceiving your own selves - Παραλογιζομενοι ἑαυτους· Imposing on your own selves by sophistical arguments; this is the meaning of the words. They had reasoned themselves into a state of carnal security, and the object of St. James is, to awake them out of their sleep.

(15) But be ye doers of the word, and not hearers only, (16) deceiving your own selves.
(15) Another admonition: therefore God's word is heard, that we may model our lives according to the laws it contains. (16) He adds reasons, and those most weighty: first, because they that do otherwise seriously harm themselves.

But be ye doers of the word,.... And they are such, who spiritually understand it; gladly receive it; and from the heart obey it, and make a sincere and ingenuous profession of it; and who submit to the ordinances it directs to, and keep them as they have been delivered; and live, and walk, becoming their profession of it. The Arabic and Ethiopic versions read, "be ye doers of the law"; and so one of Stephens's copies, as in Romans 2:13
and not hearers only; though the word should be heard swiftly and readily, and received with meekness; yet it should not be barely heard, and assented to; but what is heard should be put in practice; and especially men should not depend upon their hearing, as if that would save them; this is deceiving your own selves; such as rest upon the outward hearing of the word will be sadly deceived, and will find themselves miserably mistaken, another day; see Luke 13:25. Arguments taken from hence are like the sophisms, paralogisms, and false reasonings of sophisters, which carry a fair show, and ensnare and deceive.

If we heard a sermon every day of the week, and an angel from heaven were the preacher, yet, if we rested in hearing only, it would never bring us to heaven. Mere hearers are self-deceivers; and self-deceit will be found the worst deceit at last. If we flatter ourselves, it is our own fault; the truth, as it is in Jesus, flatters no man. Let the word of truth be carefully attended to, and it will set before us the corruption of our nature, the disorders of our hearts and lives; and it will tell us plainly what we are. Our sins are the spots the law discovers: Christ's blood is the laver the gospel shows. But in vain do we hear God's word, and look into the gospel glass, if we go away, and forget our spots, instead of washing them off; and forget our remedy, instead of applying to it. This is the case with those who do not hear the word as they ought. In hearing the word, we look into it for counsel and direction, and when we study it, it turns to our spiritual life. Those who keep in the law and word of God, are, and shall be, blessed in all their ways. His gracious recompence hereafter, would be connected with his present peace and comfort. Every part of Divine revelation has its use, in bringing the sinner to Christ for salvation, and in directing and encouraging him to walk at liberty, by the Spirit of adoption, according to the holy commands of God. And mark the distinctness, it is not for his deeds, that any man is blessed, but in his deed. It is not talking, but walking, that will bring us to heaven. Christ will become more precious to the believer's soul, which by his grace will become more fitted for the inheritance of the saints in light.

Qualification of the precept, "Be swift to hear": "Be ye doers . . . not hearers only"; not merely "Do the word," but "Be doers" systematically and continually, as if this was your regular business. James here again refers to the Sermon on the Mount (Matthew 7:21-29).
deceiving your own selves--by the logical fallacy (the Greek implies this) that the mere hearing is all that is needed.