Sometimes Rashbam will brazenly offer interpretations that are logical yet surprisingly differently from “standard” interpretations. This is the case in Deuteronomy 32:10, with a phrase that is often interpreted as “the pupil of God’s eye.”
Deuteronomy 32:10 [GOD WILL PROTECT THEM] LIKE THE ISHON OF GOD’S EYE: God will protect the Israelites in the same way that the ishon – the flesh that is drawn down over the eye, that we call palpiere [=eyelid] in the vernacular – protects the eye. It is called ishon because it covers the eye and makes things dark. So also [one should understand the word ishon in] the phrase (Psalm 17:8), “Protect me just as they eyelid (ishon) protects the pupil (bat ayin).” [Bat ayin means pupil,] as it is written (Zechariah 2:12), “[Whoever touches you] touches the pupil of his own eye (b’vavat eino).” That is [the part of the eye] with which people see, that is called prunelle [=pupil] in the vernacular. (Translation adapted from Martin Lockshin)
Most translators understand ishon as pupil, and so just as we instinctively and thoroughly protect the essential piece of our eyes, God protects Israel. However, Rashbam thinks ishon means eyelid, which still helps us understand God as protective force, but gives a twist on the meaning of the phrase. Rather than us being the “apple of God’s eye” so to speak, there is a shift – we are not God’s ishon (eyelid), but rather God’s metaphorical eyelid becomes a shield for us. God has the remarkable capacity, one might say, to keep out most harm while still allowing us to be open to the world, in the way the eyelid prevents harmful particles while allowing us to see.
For more about Rashbam, see my introduction.