אבן עזרא — שכל את ידיו כי מנשה הבכור

Q — "שכל את ידיו כי מנשה הבכור" — how is Menashe's status as bechor a CAUSE for Yaakov's crossing his hands? The pshat sense of "כי" as "because" makes the verse self-contradictory; if Menashe was the bechor, Yaakov should have placed his right hand on Menashe, not crossed away from him.

A — Ibn Ezra's answer is a single grammatical key that unlocks a dozen difficult psukim: "כי" sometimes means "אף על פי" — "although." Yaakov crossed his hands ALTHOUGH Menashe was the bechor. The cross-reference is Moshe's plea after the egel: "ילך נא אדני בקרבנו כי עם קשה ערף הוא" — "even though they are stiff-necked, forgive." Ibn Ezra lists more than ten further examples across Tanach: "רפאה נפשי כי חטאתי לך" (Tehillim — heal me although I sinned), "כי לי כל הארץ" (Shemot 19:5 per R' Marinus — although the whole earth is Mine), "שלום יהיה לי כי בשררות לבי אלך" (Devarim 29:18), "כי רב הוא" (Tehillim 25:11), "כי זקנה אמך" (Mishlei 23:22), "כי רבה היא" (Esther 1:20). A small grammatical insight that resolves stubborn local difficulties across Torah, Neviim, and Ketuvim.