S, of the Main Line, might not remember it but a few weeks ago he asked me for a Rashi I really liked. I told him I had one for Vayechi. Here it is:
“The angel who redeemed me from all evil, shall bless the lads and let my name be called on them, together with the names of my fathers, Abraham and Isaac.”
He shall bless the lads: Menashe and Ephraim.
Bizzare, right? Don't we know from the context that the "lads" are Menashe and Ephraim. We do, but we might be forgiven for small doubts. Because in Midrash Bereishis Rabba (97:3) we find the following comment: He shall bless the lads: This is Joshua and Gideon
Additionally, Joshua and Gideon have points in common with Jacob’s blessing. Aside from the obvious (Joshua is from Ephraim and Gideon is from Menashe) both were met and blessed by angles(1), and both are called "lads."(2)
It seems that Rashi worried that someone who was familiar with the midrash and the rest of the Torah, might assume that Jacob's blessing was a prophecy referring to Joshua and Gideon. It isn't. Rashi's comment on Genesis 48:16, is not meant to point out the obvious, but to protect the simple meaning of the text from what, it appears, he thought was a likely error.
(1) Joshua 5:13 and Judges 6:12
(2) Exodus 33:11 and Judges 6:15