Reference for Bava Batra 219:2
אמר רבא הנושא אשה צריך שיבדוק באחיה שנאמר (שמות ו, כג) ויקח אהרן את אלישבע בת עמינדב אחות נחשון ממשמע שנאמר בת עמינדב איני יודע שאחות נחשון היא מה תלמוד לומר אחות נחשון מכאן שהנושא אשה צריך שיבדוק באחיה תנא רוב בנים דומין לאחי האם
are to be inferred. Raba said: He who [wishes] to take a wife should inquire about [the character of] her brothers. For it is said, And Aaron took Elisheba, the daughter of Amminadab, the sister of Nahshon;<span class="x" onmousemove="('comment',' Ex. VI, 23. ');"><sup>5</sup></span> since it is stated the daughter of Amminadab, would it not he obvious that she is the sister of Nahshon? Then why should it be expressly stated, the sister of Nahshon? From here, [then], it is to be inferred that he who takes a wife should inquire about [the character of] her brothers. It was taught:<span class="x" onmousemove="('comment',' Soph. XV, 20. ');"><sup>6</sup></span> Most children resemble the brothers of the mother.