Midrash su Esodo 19:16

Further said R. Chelbo in the name of R. Huna: "He who does not cheer the bridegroom, whose wedding feast he has enjoyed, transgresses against the five voices (the passage where voice is mentioned five times) (Jer. 33, 11.) The voice of gladness, the voice of joy, the voice of the bridegroom and the voice of the bride, the voice of those who say Praise ye the Lord of Hosts." And if he does cheer him, what will his reward be? R. Simon b. Lakish said: "He will merit the Torah, which was given with five voices, as it is said (Ex. 19, 16.) And it came to pass on the third day, when it was morning, that there were thunders, and the voice of the cornet, etc.. And the voice of the cornet was, etc., And God answered him with a loud voice." R. Abuhu said: ["To cheer the bridegroom is considered meritorious] as if he brought a thanksgiving offering; for it is said (Jer. 33, 11.) Of those that bring thanksgiving offering unto the house of the Lord." R. Nachman b. Isaac said: "It is as if he had rebuilt one of the ruins of Jerusalem, for it is said (Ib.) For I will cause their captivity to return, as at the first, saith the Lord."

1) (Vayikra 9:1) ("And it was on the eighth day that Moses called to Aaron and to his sons and to the elders of Israel"): This is one of the verses that needs expounding: It is written here: "And it was on the eighth day," and elsewhere (Shemoth 19:16): "and it was on the third day." We do not know whether (this refers to) the third day of the month (Sivan) or the third day of the number (of days of separation, viz. Shemoth 19:15). Its being written (Shemoth 19:11): "… for on the third day the L–rd will go down before the eyes of all the people on Mount Sinai" and then "And it was on the third day, when it was morning etc." tells us that it is the third day of the number, and not of the month, that is being referred to. Here, too, it is written: And it was on the eighth day," and we do not know whether it is the eighth day of the number (of days of miluim [i.e., the first of Nissan]) or the eighth day of the month (of Nissan). Its being written (Vayikra 8:33): "For seven days shall He invest your hands" tells us that it is the eighth day of the number and not the eighth day of the month. That day (the first of Nissan) took ten crowns: It was first for creation of the universe; first for the (sacrificial service of the) nesi'im (the chiefs of the tribes); first for the (sacrificial service of the) Cohanim, (that service having previously been performed by the first-born, and, on the seven days of miluim, by Moses); first for the (sacrificial) service (of the daily offerings [temidim] and all of the communal offerings); first for the descent of fire (upon the altar from Heaven); first for shechitah in the north (of the altar); first for the prohibition of bamoth (temporary altars); first for roshei chodoshim (the beginnings of months); first for the reposing of the shechinah in Israel; first for the (priestly) blessing of Israel.

R. Abdimi maintained: Twenty-two thousand chariots descended with Him to Sinai. What is meant by uttereth His voice? It indicates that first there were thunders and lightnings (Exod. 19:16). After he sent forth the thunder, He gave the Torah. Hence it is said: And the Lord uttereth His voice before His army (Joel 2:11).