Halacha:

Sukkot,  Tefillah,  Yom Kippur 

Machshava:

Tefillah 

References: Succah: 41A ,  Taanit: 4B  

Description

Why do we omit Tachanun between Yom Kippur and Sukkot? It can't be because of the UPCOMING Holiday as we don't omit Tachanun DAYS before any Holiday. So there must be another reason