Genesis 1:22

ויברך אותם AND HE BLESSED THEM — Because people decreased their number, hunting them and eating them, they needed a blessing (Genesis Rabbah 11:2); it is true that beasts also were in need of a blessing, but on account of the serpent that was to be cursed in the future, He did not bless them, in order that it might not be included in the blessing. פרו BE FRUITFUL — פרו is of the same root as פרי, and means bring forth fruit. ורבו AND MULTIPLY — Had He said “Be fruitful” only, one creature might have brought forth a single one, and no more, therefore He added ורבו “and multiply”, implying that one should bring forth many.

וַיְבָ֧רֶךְ אֹתָ֛ם אֱלֹהִ֖ים לֵאמֹ֑ר פְּר֣וּ וּרְב֗וּ וּמִלְא֤וּ אֶת־הַמַּ֙יִם֙ בַּיַּמִּ֔ים וְהָע֖וֹף יִ֥רֶב בָּאָֽרֶץ׃

And God blessed them, saying, Be fruitful, and multiply, and fill the waters in the seas, and let birds multiply in the earth.