The verse already says that "Yaakov's eyes were weak from old age;" why does it see fit to add that "he could not see"?
Seforno: Because Yaakov wanted to bless Efrayim and Menasheh; and in order to bless with a full heart, one needs to see the object of one's blessing. 1
Ohr ha'Chayim: Refer to 48:10:152:2.
Ha'amek Davar: He wanted to look well at them to increase love, but he could not. To compensate, he did other actions - touching and filling his mind with love.
As we find in Parshas Balak (Bamidbar 23:13), and in V'Zos Ha'Berachah (Devarim 34:1). (The former was in order to curse! It is clear to Seforno that the same applies to both Berachos and curses - PF.)
What is the significance of the fact that Yaakov kissed and hugged Efrayim and Menasheh?
Seforno: So that his soul should cleave to theirs, for the Berachah to take effect. 1
Hadar Zekenim: Shechinah dwells only amidst Simchah.
Ha'amek Davar: Refer to 48:10:1:3.
Pasuk 48:8 said that Yaakov saw them! Why does it say now that he could not see?
Moshav Zekenim, Riva citing R. Tam: He saw the form of people, but did not know who they were.
Bechor Shor: He could not understand what he saw.
Why does it say that he kissed and hugged "Lahem" (and not 'Osam')?
Ramban (to 29:11, citing Ibn Ezra): Neshikah followed by the prefix 'Lamed' denotes kissing on the hand or on the shoulder, and not on the mouth.
Ohr ha'Chayim: He could not see well, and did not kiss and hug them in the proper place.
Ha'amek Davar: This implies that they kissed and hugged each other, 1 to arouse mutual love.
Why did he kiss them, and afterwards hug them? Lavan and Esav first hugged [Yaakov], and afterwards kissed him (see 29:13, 33:4)!
