Another interpretation: “This month shall be for you” – why did the Holy One blessed be He say this to Moses and Aaron? It is because sanctification of the month is [done] with three. When the Holy One blessed be He sought to sanctify the month, the Holy One blessed be He said to Moses and Aaron: I and [the two of] you will sanctify the month. That is what is written: “The Lord spoke to Moses and to Aaron.”
However, intercalation of the year49Adding a month to the year to synchronize the lunar calendar with the solar calendar. is done by ten elders. When our Rabbis assembled to intercalate the year, ten expert elders would assemble in the study hall, and the Av Beit Din [the senior member of the court] was among them. They would lock the doors and deliberate over the matter all night. At midnight, they would say to the Av Beit Din: ‘We seek to intercalate the year so that this year will be thirteen months; will you join us in this decree?’
He would say to them: ‘I am with you in your opinion.’ At that moment, light would emerge from the study hall and come before them, and they would know that God has consented to them, as it is stated: “To the upright He shines a light in the darkness” (Psalms 112:4). What they decree, the Holy One blessed be He agrees with them, as it is stated: “I will cry to God Most High, to God who accomplishes it for me” (Psalms 57:3).
May the name of the Holy One blessed be He be praised, that creatures decree and He consents, as it is stated: “The righteous rules with the fear of God” (II Samuel 23:3). From where is it derived to convene with ten elders? It is as it is stated: “Wisdom bolsters the wise man more than ten rulers who are in a city” (Ecclesiastes 7:19). Likewise, during the reign of Solomon, when Solomon would intercalate the year, he would assemble seven elders before him, as it is stated: “A wise man is lazy in his eyes, more than seven who respond sensibly” (Proverbs 26:16).
What is “A wise man is lazy in his eyes?” It is that Solomon would keep his mouth closed, so as not to speak before one who is greater than he, and so it says: “When you sit to eat with a ruler, consider well what is before you” (Proverbs 23:1), and it says: “Put a knife to your throat, if you are a man with self-control” (Proverbs 23:2). Solomon, Natan the prophet, and Gad the seer were there, for a total of ten.