Numbers 30:1

ויאמר משה אל בני ישראל AND MOSES TOLD THE CHILDREN OF ISRAEL — This is stated to separate this subject (of sacrifies) from the following (vows). Such is the opinion of R. Ishmael. What it means is: since up to now we have the words of the Omnipresent to Moses (Numbers 28:1—2: “And the Lord said to Moses, ‘Command the children of Israel, etc.’ ”) and the chapter about vows that follows begins with an utterance of Moses (“And Moses spake”), it is necessary first to make a break by stating that Moses in turn told this section to Israel (“And Moses told etc.”), for if this were not done it would imply that he did not tell them this section about the sacrifices, but began his address with the chapter about vows (Sifrei Bamidbar 152).

וַיֹּ֥אמֶר מֹשֶׁ֖ה אֶל־בְּנֵ֣י יִשְׂרָאֵ֑ל כְּכֹ֛ל אֲשֶׁר־צִוָּ֥ה יְהֹוָ֖ה אֶת־מֹשֶֽׁה׃ {פ}

And Moshe told the children of Yisra᾽el according to all that the Lord commanded Moshe.