Moses was learned - Or, was “instructed.” It does not mean that he had that learning, but that he was carefully “trained” or educated in that wisdom. The passage does not express the fact that Moses was distinguished for “learning,” but that he was carefully “educated,” or that pains were taken to make him learned.
In all the wisdom ... - The learning of the Egyptians was confined chiefly to astrology, to the interpretation of dreams, to medicine, to mathematics, and to their sacred science or traditionary doctrines about religion, which were concealed chiefly under their hieroglyphics. Their learning is not infrequently spoken of in the Scriptures, 1 Kings 4:30; compare Isaiah 19:11-12. Their knowledge is equally celebrated in the pagan world. It is known that science was carried from Egypt to Phoenicia, and thence to Greece; and not a few of the Grecian philosophers traveled to Egypt in pursuit of knowledge. Herodotus himself frankly concedes that the Greeks derived very much of their knowledge from Egypt. (See Rawlinson’s Herodotus, vol. 2, pp. 80, 81; Herodotus, bk. 2, pp. 50, 51.)
And was mighty - Was powerful, or was distinguished. This means that he was eminent in Egypt before he conducted the children of Israel forth. It refers to his addresses to Pharaoh, and to the miracles which he performed “before” their departure.
In words - From Exodus 4:10, it seems that Moses was “slow of speech, and of a slow tongue.” When it is said that he was mighty in words, it means that he was mighty in his communications to Pharaoh, though they were spoken by his brother Aaron. Aaron was in his place, and “Moses” addressed Pharaoh through him, who was appointed to deliver the message, Exodus 4:11-16.
Deeds - Miracles, Exodus 7, etc.