פירוש על שמות 6:27

הם המדברים וגו׳ THESE ARE THEY WHO SPAKE TO PHARAOH — It was they who received the command to speak to Pharaoh (cf. v. 26), and it was they who carried it out by actually speaking to him (cf. e.g. Exodus 7:7).

הם המדברים, in connection with דבור, speaking, Moses is still mentioned first followed by Aaron, although in order of birth Aaron preceded Moses, being the firstborn.

הם המדברים, they were fit to be the spokesmen to Pharaoh and to be listened to by him with respect.

הם המדברים אל פרעה מלך מצרים, they were the ones who talked tough to Pharaoh the king of Egypt. They spoke to him as does a king who issues decrees. The Torah also wanted to remind us that though G'd had instructed Moses to speak, Aaron spoke also, as I shall explain in greater detail on verse 28.

These are Moshe and Aharon. In Pharaoh’s view Moshe was the greater one, for he already knew of his reputation and his wisdom, but Aharon was unknown to him.

הוא משה ואהרן THESE ARE MOSES AND AARON — they remained always the same in carrying out their mission and in their integrity from beginning to end (cf. Megillah 11a).

הוא משה ואהרון, they are the same Moses and Aaron, etc. The Torah wants to convey that Moses and Aaron enjoyed equal status; this is why sometimes Aaron is mentioned first whereas other times Moses is mentioned first. The Torah makes this point doubly clear by referring to both of them in the singular i.e. הוא, as opposed to הם. The Torah uses the plural also i.e. הם המדברים. This is because Moses and Aaron did not speak simultaneously but they alternated when speaking to Pharaoh.