4094 - Explained to Rabbi Dubov a passage in Tanya Chapter 7.

There were, G-d forbid, no ill feelings when I commented about you davening at length. The Rebbe Maharash answered Reb Yisrael Salanter why Chasidim daven long, and he said because, according to one opinion, prayer only accomplishes half." https://www.torahrecordings.com/rebbe/igroskodesh/012/005/4094