Don

On the various Jewish sects in the 2nd temple Judaism(s), we know about the Sadducees and Pharisees and Essenes and Zealots and Herodians and the Way.  The Pharisees had 2 main schools, Shammai and Hillel, their debates are recorded in the Mishnah.  The school of Hillel evolved into orthodox rabbic Judaism after the temple was destroyed, all the rest were wiped out by 100 except the Way evolved into Christianity once the gentiles came in.

On love, this is the MAIN sign of a believer, esp. love of the brethren.  See 1 Cor 13 and elsewhere.  God dealt with me when I thought that being right was more important than love.