On our sister website: Judianity we have several articles on this challenging subject not least because of Christ's comment in Matthew 23:
Matthew 23:1-3
1 ¶ Then spake Jesus to the multitude, and to his disciples,
2 Saying, The scribes and the Pharisees sit in Moses’ seat:
3 All therefore whatsoever they bid you observe, that observe and do; but do not ye after their works: for they say, and do not.