Jesus warned His followers against “the leaven of the Pharisees”. Jesus was speaking of the false doctrine of those in Moses’ seat. The Pharisees believed in the resurrection and in the reality of spirits and angels. Most importantly, they believed in the literal interpretation of scripture. These are all true and good doctrines, so what was Jesus specifically referring to?
Manmade doctrines
Jesus was speaking primarily about doctrines rather than the accuracy of the doctrines themselves. Jesus even told His followers,(Matt 23:3-4, KJV).