The rabis and the religious scholars should have forbidden them from saying what is sinful and doing what is unlawful. Indeed, you can take the sayings and the opinions of any person who works in any field, such as a physicist, chemist, doctor, craftsman, merchant, farmer, and politician without taking into consideration his behavior, except for someone who has religious knowledge, it is not permissible for him to say to you:

Take my knowledge and do not be indifferent to my work,

reap the fruits and pick the aloes for the fire.

This is not acceptable; because the Prophet (saws) would not command anything unless he was the first to comply with it, so the issue is of behavior for those who carry the mission, if they are rabbis or scholars, so the one who calls to Allah (swt) should not say what he does not do. Hence, the rabis has not forbade the Jews from committing sins.

(  لَبِئْسَ مَا كَانُوا يَصْنَعُونَ… ) (…How wretched is what they have been practicing): Allah (swt) uses the word (practicing), not (doing) or saying) although when He (swt) addresses the believers He says:

 يَا أَيُّهَا الَّذِينَ آمَنُوا لِمَ تَقُولُونَ مَا لَا تَفْعَلُونَ

(O you who have believed, why do you say what you do not do?) (As-Saff: 2)

Because they did not only commit evil and devoured what is unlawful, rather they uttered sinful words so their act combines doing and saying.