Note 8.Hinei Lo Tova Hashemua Tanya Lectures – Kuntress Acharon

Davening may not be a DeOraisa (a Biblical commandment) but it entails many of the most important DeOraisas and “Super Mitzvos” (i.e. higher than individual limbs (of Atzilus)). Therefore Davening must be done A. with the Minyan and it must be done B. properly. If one is in a rush he can Daven alone even if there is a minyan in his city. The Minyan must be allowed to Daven at the right pace.