And Jacob did so, and fulfilled her week: and he gave him Rachel his daughter to wife also.

Jamieson-Fausset-Brown Bible Commentary

28. gave him Rachel also-It is evident that the marriage of both sisters took place nearly about the same time, and that such a connection was then allowed, though afterwards prohibited (Le 18:18).

Matthew Henry's Concise Commentary

29:15-30 During the month that Jacob spent as a guest, he was not idle. Wherever we are, it is good to employ ourselves in some useful business. Laban was desirous that Jacob should continue with him. Inferior relations must not be imposed upon; it is our duty to reward them. Jacob made known to Laban the affection he had for his daughter Rachel. And having no wordly goods with which to endow her, he promises seven years' service Love makes long and hard services short and easy; hence we read of the labour of love, Heb 6:10. If we know how to value the happiness of heaven, the sufferings of this present time will be as nothing to us. An age of work will be but as a few days to those that love God, and long for Christ's appearing. Jacob, who had imposed upon his father, is imposed upon by Laban, his father-in-law, by a like deception. Herein, how unrighteous soever Laban was, the Lord was righteous: see Jud 1:7. Even the righteous, if they take a false step, are sometimes thus recompensed in the earth. And many who are not, like Jacob, in their marriage, disappointed in person, soon find themselves, as much to their grief, disappointed in the character. The choice of that relation ought to be made with good advice and thought on both sides. There is reason to believe that Laban's excuse was not true. His way of settling the matter made bad worse. Jacob was drawn into the disquiet of multiplying wives. He could not refuse Rachel, for he had espoused her; still less could he refuse Leah. As yet there was no express command against marrying more than one wife. It was in the patriarchs a sin of ignorance; but it will not justify the like practice now, when God's will is plainly made known by the Divine law, Le 18:18, and more fully since, by our Saviour, that one man and woman only must be joined together, 1Co 7:2.