In the 2nd aliyah of Parshas Kedoshim, we learn the mitzva of V'ahavta L'reiacha Kamocha, loving our friend as ourselves. This concept is the greatest principle in the Torah, as is taught by Rabi Akiva. During this period of Sefiras Ha'omer we are building up to Matan Torah when Klal Yisroel stood under Har Sinai like one man with one heart. In order to achieve that ultimate unity, we need to separate ourselves from our physicality and connect to each other in a spiritual way by working to achieve a higher level of kedusha. The period of Sefirah is when the students of Rabi Akiva died because they did not give kavod
(honor) to each other. As long as they remained separate entities the Torah was not able to be sustained. We spend this period of time working on ourselves to truly give kavod to each other and become one in order to bring ourselves to a level of accepting the Torah.