O house of Jacob He sharply rebukes the Jews by holding out the example of the Gentiles; for since, in consequence of the spread of his kingdom, God would give law to all nations from Mount Zion, so as to ingraft them into the body of his chosen people, nothing could be more strange than that the house of Jacob should revolt from him, and that, when strangers were drawing near, the members of the household, who ought to have been foremost, should withdraw. This is, therefore, not only an exceedingly vehement exhortation, but also a heavy and sharp complaint. Accordingly, he addresses them by an honorable name, saying, O house of Jacob, come; that he may express more strongly their ingratitude, which appeared in twist that though they were in the Church God's first-born, they utterly renounced that right of inheritance which they held in common with others. There is, therefore, an implied comparison, as if he had said, "Lo, the Gentiles flow together to Mount Zion, and every one exhorts and urges on his neighbor; they submit to receive instruction from God, and to be reproved by him and why do you, O Israelites, you who are the inheritance of God, why do you draw back? Shall the Gentiles submit to God, and shall you refuse to acknowledge his authority? Has so great a light been kindled in every part of the world, and shall you not be enlightened by it? Shall so many waters flow, and will you not drink? What madness is this, that when the Gentiles run so eagerly, you sit still in idleness?" And we will walk in the light of the Lord When he adds we will walk, he means that the light is placed before their feet, but that they disregard it by shutting their eyes, and even extinguish it as far as lies in their power; and yet its brightness draws to it distant nations.

O house of Jacob - This is a direct address, or exhortation, of the prophet to the Jews. It is made in view of the fact that God had gracious purposes toward them. He intended to distinguish them by making them the source of blessings to all nations. As this was to be their high destiny, he exhorts them to devote themselves to him, and to live to his honor. The word "house" here means the "family, or nation." The phrase is applied to the Jews because their tribes were descended from the twelve sons of Jacob.
Let us walk - Let us "live." The word "walk" is often used to denote human life or conduct; compare Isaiah 2:3; Romans 6:4; Romans 8:1; 1-Corinthians 5:7; Galatians 6:16,
In the light of the Lord - The sense of this is: Let us obey the commandments of Yahweh; or, as the Chaldee expresses it, 'Let us walk in the doctrine of the law of the Lord.' The idea may be thus expressed: 'Let us not walk in the darkness and error of sin and idolatry, but in the light or instruction which God sheds upon us by his law. He teaches us what we should do, and let us obey him.' "Light" is often, in the Scriptures, thus put for instruction, or teaching; compare the note at Matthew 4:16; note at John 1:4; also, note at Ephesians 5:8.

O house of Jacob, come ye, and let us (l) walk in the light of the LORD.
(l) Seeing the Gentiles will be ready, make haste, and show them the way to worship God.

O house of Jacob,.... This is either an exhortation of the prophet to the men of his generation, to attend to the light of the law, which the Lord had given them, as Aben Ezra and Kimchi; or rather, as the Targum and Jarchi suggest, an exhortation of the nations to the people of Israel, and are indeed the words of the converted Gentiles to the people of the Jews, being concerned for their conversion and spiritual welfare, as will appear in the latter day; when they will not only encourage one another to go up to the house of the Lord, as in the preceding verses, but will be very solicitous that the Jews, the posterity of Jacob, share with them in all that light and glory that shall be risen upon Zion; as follows:
come ye, and let us walk in the light of the Lord; meaning either Christ, in whom the light of the knowledge of the glory of God is given, and the glory of all the perfections of the divine nature is displayed; who is that light that dwells with the Lord, was sent forth by him, and came into this world as the light of it, and is given for a light to the Gentiles, as well as the glory of the people of Israel; and who is the author of all light; of corporeal light, in the first creation; of the sun, moon, and stars; of the light of nature in every man; of the light of the Gospel of the grace of God; of the spiritual light of grace in the hearts of his people; and of the light of eternal glory: or else the Gospel is intended, called the light of the glorious Gospel of Christ, 2-Corinthians 4:4 by which some are only notionally enlightened, and some spiritually and savingly, when it is attended with the spirit of wisdom and revelation in the knowledge of Christ: or rather, the light of the latter day glory, which includes the other two; when Christ and his Gospel will be more clearly revealed and seen, not only by the watchmen, who will see eye to eye, but by all the saints; when the light of the moon shall be as the light of the sun, and the light of the sun sevenfold as the light of seven days, and the whole earth shall be lightened with its glory, Isaiah 30:26 and to "walk" in this light, as it respects Christ, is to walk by faith in him, to go on in believing views of him, and to walk in imitation of him, and as he directs; and as it respects the Gospel, it is to embrace it, profess it, hold it fast, and hold it forth; and to walk as that prescribes and guides, and as becomes it; and to walk as children of the light, wisely and circumspectly; worthy of the calling of God, of the grace he calls by, and the kingdom he calls to: and to walk in the light of the latter day glory is to enjoy it, and share in all the blessings of it, with perseverance therein, through the grace of God; and such walking is pleasant and comfortable; such shall have the communion of God and Christ, and fellowship one with another, and at last enjoy the light of life.

The connection is: As Israel's high destiny is to be a blessing to all nations (Genesis 12:3), let Israel's children walk worthy of it (Ephesians 5:8).

Isaiah presents himself to his contemporaries with this older prophecy of the exalted and world-wide calling of the people of Jehovah, holds it up before them as a mirror, and exclaims in Isaiah 2:5, "O house of Jacob, come, let us walk in the light of Jehovah." This exhortation is formed under the influence of the context, from which Isaiah 2:2-4 are taken, as we may see from Micah 4:5, and also of the quotation itself. The use of the term Jacob instead of Israel is not indeed altogether strange to Isaiah (Isaiah 8:17; Isaiah 10:20-21; Isaiah 29:23), but he prefers the use of Israel (compare Isaiah 1:24 with Genesis 49:24).With the words "O house of Jacob" he now turns to his people, whom so glorious a future awaits, because Jehovah has made it the scene of His manifested presence and grace, and summons it to walk in the light of such a God, to whom all nations will press at the end of the days. The summons, "Come, let us walk," is the echo of Isaiah 2:3, "Come, let us go;" and as Hitzig observes, "Isaiah endeavours, like Paul in Romans 11:14, to stir up his countrymen to a noble jealousy, by setting before them the example of the heathen." The "light of Jehovah" ('or Jehovah, in which the echo of v'yorenu in Isaiah 2:3 is hardly accidental; cf., Proverbs 6:23) is the knowledge of Jehovah Himself, as furnished by means of positive revelation, His manifested love. It was now high time to walk in the light of Jehovah, i.e., to turn this knowledge into life, and reciprocate this love; and it was especially necessary to exhort Israel to this, now that Jehovah had given up His people, just because in their perverseness they had done the very opposite. This mournful declaration, which the prophet was obliged to make in order to explain his warning cry, he changes into the form of a prayerful sigh.

The light - Take heed that you do not reject that light which is so clear that even the blind Gentiles will discern it.