Because thou art my brother, etc. - Though thou art my nearest relative, yet I have no right to thy services without giving thee an adequate recompense. Jacob had passed a whole month in the family of Laban, in which he had undoubtedly rendered himself of considerable service. As Laban, who was of a very saving if not covetous disposition, saw that he was to be of great use to him in his secular concerns, he wished to secure his services, and therefore asks him what wages he wished to have.

And Laban said unto Jacob, because thou art my brother,.... Or nephew, his sister's son; see Gill on Genesis 29:12,
shouldest thou therefore serve me for nought? nearness of kin was no reason why he should serve him freely, or for nothing, but rather why he should be more kind to him than to a stranger, and give him better wages:
tell me, what shall thy wages be? by the day, or month, or year; signifying he was willing to give him anything that was just and reasonable, which was very well spoken; and this gave Jacob a fair opportunity of opening his mind more freely to him, and for answering a principal end for which he came, as follows:

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, Hebrews 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 Judges 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, Leviticus 18:18, and more fully since, by our Saviour, that one man and woman only must be joined together, 1-Corinthians 7:2.

Jacob's Double Marriage. - After a full month ("a month of days," Genesis 41:4; Numbers 11:20, etc.), during which time Laban had discovered that he was a good and useful shepherd, he said to him, "Shouldst thou, because thou art my relative, serve me for nothing? fix me thy wages." Laban's selfishness comes out here under the appearance of justice and kindness. To preclude all claim on the part of his sister's son to gratitude or affection in return for his services, he proposes to pay him like an ordinary servant. Jacob offered to serve him seven years for Rachel, the younger of his two daughters, whom he loved because of her beauty; i.e., just as many years as the week has days, that he might bind himself to a complete and sufficient number of years of service. For the elder daughter, Leah, had weak eyes, and consequently was not so good-looking; since bright eyes, with fire in them, are regarded as the height of beauty in Oriental women. Laban agreed. He would rather give his daughter to him than to a stranger.
(Note: This is the case still with the Bedouins, the Druses, and other Eastern tribes (Burckhardt, Voleny, Layard, and Lane).
Jacob's proposal may be explained, partly on the ground that he was not then in a condition to give the customary dowry, or the usual presents to relations, and partly also from the fact that his situation with regard to Esau compelled him to remain some time with Laban. The assent on the part of Laban cannot be accounted for from the custom of selling daughters to husbands, for it cannot be shown that the purchase of wives was a general custom at that time; but is to be explained solely on the ground of Laban's selfishness and avarice, which came out still more plainly afterwards. To Jacob, however, the seven years seemed but "a few days, because he loved Rachel." This is to be understood, as C. a Lapide observes, "not affective, but appretiative," i.e., in comparison with the reward to be obtained for his service.

Because thou art my brother - That is, kinsman. Should thou therefore serve me for nought? - No, what reason for that? If Jacob be so respectful as to give him his service without demanding any consideration for it, yet Laban will not be so unjust as to take advantage either of his necessity, or of his good nature. It appears by computation that Jacob was now seventy years old when he bound himself apprentice for a wife; probably Rachel was young and scarce marriageable when Jacob came first, which made him the more willing to stay for her till his seven years were expired.