On the first day of the second month, in the second year following the exodus from the land of Egypt, the LORD spoke to Moses in the wilderness of Sinai, in the Tent of Meeting, saying:
וידבר… במדבר סיני … באחד לחדש וגו׳ AND [THE LORD] SPOKE [UNTO MOSES] IN THE DESERT OF SINAI … ON THE FIRST DAY OF THE [SECOND] MONTH … [TAKE YE THE SUM OF ALL THE CONGREGATION] etc. — Because they were dear to him, He counts them every now and then: when they went forth from Egypt He counted them (Exodus 12:37), when many of them fell in consequence of their having worshipped the golden calf He counted them to ascertain the number of those left (cf. Rashi Exodus 30:16); when he was about to make His Shechinah dwell amongst them (i. e. when He commanded them to make a Tabernacle), He again took their census; for on the first day of Nisan the Tabernacle was erected (Exodus 40:2) and shortly afterwards, on the first day of Iyar, He counted them.
ההוא מינא דחזייה לרבא דקא מעיין בשמעתא ויתבה אצבעתא דידיה תותי כרעא וקא מייץ בהו וקא מבען אצבעתיה דמא אמר ליה עמא פזיזא דקדמיתו פומייכו לאודנייכו אכתי בפחזותייכו קיימיתו ברישא איבעיא לכו למשמע אי מציתו קבליתו ואי לא לא קבליתו אמר ליה אנן
The Gemara relates that a heretic saw that Rava was immersed in studying halakha, and his fingers were beneath his leg and he was squeezing them, and his fingers were spurting blood. Rava did not notice that he was bleeding because he was engrossed in study. The heretic said to Rava: You impulsive nation, who accorded precedence to your mouths over your ears. You still bear your impulsiveness, as you act without thinking. You should listen first. Then, if you are capable of fulfilling the commands, accept them. And if not, do not accept them. He said to him: About us,
דסגינן בשלימותא - התהלכנו עמו בתום לב כדרך העושים מאהבה וסמכנו עליו שאל יטעננו בדבר שאל נוכל לעמוד:
He [also] used to say: If I am not for myself, who is for me? But if I am for my own self [only], what am I? And if not now, when?