When Pharaoh shall speak to you, saying, Shew a miracle. It is obvious that there would have been an impropriety in Moses and Aaron offering a sign to Pharaoh until he asked for one. They claimed to be ambassadors of Jehovah, and to speak in his name (Exodus 5:1). Unless they were misdoubted, it was not for them to produce their credentials. Hence they worked no miracle at their former interview. Now, however, the time was come when their credentials would be demanded, and an express command was given them to exhibit the first "sign."
HOMILETICS
God assigns to each man his intellectual grade.
Three different intellectual grades are here set before us—that of the thinker, that of the expounder, and that of the mere recipient. Pharaoh, notwithstanding his exalted earthly rank, occupies the lowest position. He is to hang on the words of Aaron, who is to be to him as a prophet of the Most High. Aaron himself is to hang on the words of Moses, and to be simply his mouthpiece. Moses is to stand to both (compare Exodus 4:16) as God. And here note, that the positions are not self-assumed—God assigns them. So there are leaders of thought in all ages, to whom God has given their intellectual gifts, whom he has marked out for intellectual pre-eminency, and whom he makes to stand to the rest of men as gods. Sometimes they are their own prophets—they combine, that is, the power of utterance with the power of thought. But very often they need an interpreter. Their lips are uncircumcised. They lack eloquence; or they even lack the power of putting their thoughts into words, and require a "prophet," to publish their views to the world. The "prophet-interpreter" occupies a position very much below theirs, but still one requiring important and peculiar gifts, such as God alone can give. He must have the intelligence to catch the true bearing, connection, and force of the ideas presented to him, often in rude and uncouth language, like statues rough-hewn. He must be able to work up the rough material into presentable form. He must have a gift of language, if not a gift of speech. The great mass of men occupy a lower rank than either of these; they can neither originate, nor skilfully interpret; it remains that they be content to receive. God has given to them their humble position, as he has given to the others their loftier ones. They should cultivate their receptivity. They should be satisfied to listen and learn. They should remember that if, on the one hand, οὗτος μὲν πανάριστος ὂς αὐτὸς πάντα νοήσῃ—on the other, ἐσθλὸς δ αυ} ka)kei=noj o$j eu) ei)po&nti pi&qhtai