Megillah 13B

״לא יגרע מצדיק עיניו״⁠ — בשכר צניעות שהיתה בה ברחל זכתה ויצא ממנה שאול, ובשכר צניעות שהיה בו בשאול זכה ויצאת ממנו אסתר.

“He withdraws not His eyes from the righteous; but with kings upon the throne He establishes them forever, and they are exalted” (Job 36:7)? This teaches that in reward for the modesty shown by Rachel she merited that Saul, who was also modest, should descend from her, and in reward for the modesty shown by Saul, he merited that Esther should descend from him.

ומאי צניעות היתה בה ברחל? דכתיב: ״ויגד יעקב לרחל כי אחי אביה הוא״. וכי אחי אביה הוא? והלא בן אחות אביה הוא?

The Talmud explains: What was the modesty shown by Rachel? It is as it is written: “And Jacob told Rachel that he was her father’s brother, and that he was Rebecca’s son” (Genesis 29:12). It may be asked: Was he, Jacob, in fact her father’s brother? But wasn’t he the son of her father’s sister?

אלא, אמר לה: מינסבא לי? אמרה ליה: אין, מיהו אבא רמאה הוא ולא יכלת ליה. אמר לה: אחיו אנא ברמאות. אמרה ליה: ומי שרי לצדיקי לסגויי ברמיותא? אמר לה, אין: ״עם נבר תתבר ועם עקש תתפל״.

Rather, it must be understood that when Jacob met Rachel, he said to her: Will you marry me? She said to him: Yes, but my father, Laban, is a swindler, and you will not be able to outwit him. Jacob alleviated her fears, as he said to her that he is her father’s brother, referring not to their familial affiliation but rather to his ability to deal with her father on his level, as if to say: I am his brother in deception. She said to him: But is it really permitted for the righteous to be involved in deception? He said to her: Yes, it is permitted when dealing with deceptive individuals, as the verse states: “With the pure you will show yourself pure, and with the perverse you will show yourself subtle” (II Samuel 22:27), indicating that one should deal with others in the manner appropriate for their personality.