Rashi on Genesis 48:8/רש"י על בראשית מ״ח:ח׳

1וירא ישראל את בני יוסף AND ISRAEL SAW JOSEPH’S SONS — he wished to bless them but the Divine Presence departed from him because he saw that from Ephraim would be born the wicked kings Jeroboam and Ahab, and from Manasseh Jehu and his sous (Midrash Tanchuma, Vayechi 6).

2ויאמר מי אלה AND HE SAID “WHO ARE THESE?” — Whence come these who are unfitted for blessing?