Counting The Omer: A Long Chol HaMoed
The days between the last day of Pesach and the festival of Shavuot may be considered as somewhat like Chol Hamoed, the Intermediate days of Pesach and Succot. (Rabbeinu Bachya, Leviticus 23:16)
His teaches us that God bestows extra Influence during this period, as He does during Chol Hamoed. The influence of Sefirah is God helping those who strive for purity. (Sefat Emet, Emor, 5642)
The days of the Sefirah purify our souls, “Mispar Nafshoteichem.” Imrei Shefer
See too the Chatam Sofer, Emor, on this verse.