Genesis 29:15 - Wesley's Explanatory Notes

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.