Why G d waited 3 months after Egypt to give Torah to the Jews

from Daas Torah - translation copyrighted

Ohr HaChaim (Shemos 19:1): In the third month after the redemption of the children of Israel…on that same day they came to Sinai. It is difficult to understand why G d — despite His great love for the Jews and strong desire to give them their bride the Torah —  waited until the third month after the redemption from Egypt.  If you suggest that it was because of the distance that needed to be traveled, but we saw G d miraculously shorted the distance to speed up Rifka’s marriage to Yitzchok (Bereishis Rabbah 59:11).  We would surely have expected that G d would have done the same for the Jewish people. Consequently G d gave a  justification for the delay. It  was not the result of a lack of desire of the bride but rather that the groom (the Jewish people) were not properly prepared. The Jews were not prepared for the wedding with Torah since they had spent years in a spiritually polluted land  and had absorbed its pollution. Consequently they  needed to count for a 7 week period in a manner similar to a woman before she becomes purified. The Zohar indicates that this 7 week period between Pesach and Shavuos should be viewed as 7 times the normal 7 day period of purification. Therefore when this verse says “3 months of the leaving of Egypt”, it means the delay of 3 months was because of fact that they had left Egypt [and they needed extra purification]. A proof for this understanding is that this verse states when they had almost recovered spiritually — which was the first day of the 3rd month — they immediately arrived at Sinai. …