Rashi on Numbers 13:31/רש"י על במדבר י״ג:ל״א

1חזק הוא ממנו [FOR] THEY ARE STRONGER ממנו — They said this, — if this were at all possible (i.e. if one may be permitted to say so of God) — with reference to the Omnipresent (ממנו, stronger than “He”, they thus uttered blasphemy) (Sotah 35a; Arakhin 15a).