God spoke to Moses in the Sinai Desert, in the Communion Tent on the first [day] of the second month in the second year of the Exodus, saying:
Vayedaber Adonay el-Moshe bemidbar Sinay be'Ohel Mo'ed be'echad lachodesh hasheni bashanah hashenit letsetam me'erets Mitsrayim lemor.
|first day of the second month|
According to most authorities, this was 1 lyyar, two weeks after Passover (cf. Seder Olam 8). However, one source apparently indicates that is was 1 Marcheshvan, before the Tabernacle was erected, and that this is the count mentioned in Exodus 30:12, 38:26 (BeMidbar Rabbah 1:10; Hadar Zekenim). See Numbers 1:2.