Comentario sobre Génesis 9:7

ואתם פרו ורבו AND YE, BE FRUITFUL AND MULTIPLY — According to the real sense, the first time this mas said to man (Genesis 9:1) it was said as a blessing (an assurance that they would be fruitful); here it is a command (Ketubot 5a). According to the Midrashic explanation this command is mentioned here after the mention of murder in order to liken one who abstains from having children to one who sheds blood (Yevamot 63b).

AND YOU, BE YE FRUITFUL, AND MULTIPLY. The plain meaning thereof is as its Midrash, i.e., that it is a commandment.²⁰³Ibid., 59b. A similar verse mentioned with reference to Adam,²⁰⁴Above, 1:28. also one with reference to the sons of Noah²⁰⁵Verse 1 here. in conjunction with the statement that G-d blessed them, constitutes a blessing, just as it is said concerning the fish.²⁰⁶Above, 1:22. Now because He spoke here of the other living things and said, that they may swarm in the earth, and be fruitful, and multiply upon the earth,²⁰⁷Ibid., 8:17. He said here, And you — man — be ye fruitful and multiply. He continued saying, swarm in the earth, and multiply therein, in order to repeat the commandment for the purpose of emphasis, thus stating that they should be engaged in it with all power [since those who came forth from the ark were few]. Perhaps He commanded them concerning the settlement of the whole earth, as I have explained in Seder Bereshith.²⁰⁴Above, 1:28.
Now Rashi wrote, “According to the plain interpretation, the first time [this was said to man it was said] as a blessing; here it is a command. According to the Midrashic explanation, [this command is mentioned here after the prohibition of murder] in order to liken one who abstains from having children to one who sheds blood.” Now the Rabbis have derived this Midrash only from the juxtaposition of the verses, but the verse itself was written as a commandment, and the first [time this was said to man it was] as a blessing. [This is contrary to Rashi who implies that the Midrashic explanation differs from the plain interpretation.] And so the Rabbis have said in Tractate Sanhedrin,²⁰³Ibid., 59b. “But the commandment to be fruitful which was declared to the sons of Noah — as it is written, And you, be ye fruitful and multiply,….”

ואתם פרו ורבו, not only must you not diminish the human population on earth, but you are commanded to increase it by being fruitful and by multiplying.