The Portion read this Shabbat Chol HaMo’ed (and also Shabbat Chol HaMo’ed Pesach) relates the story of what happened after the Israelites built the Golden Calf and Moshe had to receive the second Ten Commandments to replace the ones he shattered. Hashem tells him: PSOL LECHA SHNE LUCHOT AVANIM KARISHONIM, “…Carve for yourself two stone Tablets like the first ones…”. (Ex. 34,1) Hashem had prepared the first Tablets Himself. Why now was Moshe instructed to prepare them?
The reason could very well be because Hashem prepared the first ones and also inscribed them and the people felt it will be impossible to keep the Torah since it was given by a heavenly process and was not fit for man to live by. That is why they built the Golden Calf since they needed a faith created by man. Hence Hashem told Moshe to carve the Tablets himself. This was to demonstrate that the teachings of the Torah can be lived by man.
That is why we read this Portion on Chol Hamo’ed Pesach and Succot. During Pesach, to demonstrate that the freedom gained during the Exodus can only survive if it is accompanied by the Torah. During Succot we demonstrate that we live by the Torah and go into flimsy huts to show that we have faith in Hashem and in his Torah.