Komentaryong Sumisipi para sa Mga Awit 138:3

ותצפנהו שלשה ירחים, “she kept him hidden for three months.” Moses was born on the seventh of Adar; the Egyptians had waited for Yocheved to give birth at the end of nine months as was customary. These nine months would have expired on the sixth of Sivan. The Torah does not use the word חדשים to describe “months” but ירחים, as normally you would have two months with 30 days each and one month of 29 days in between. In this instance the three months were reversed i.e. two months of 29 days and one month of 30 days giving us a total of 58 days for the period the Torah describes. The end of this period occurred on the sixth day of Sivan (the day the Torah would be given 81 years later). Moses was exposed to the waters of the Nile on that very date. The Torah hints that on the date that Moses was exposed to the cruel fate of death in the river he was compensated many years later for ascending to heaven via Mount Sinai in order to receive the Tablets. This may be what David had in mind when he said (Psalms, 138,3) “on the day I called, You answered me, You inspired me with courage.”