(Verily, those who conceal what Allah has sent down of the Book.) Meaning the Jews who concealed their Book's descriptions of Muhammad ﷺ, all of which testify to his truth as a Messenger and a Prophet. They concealed this information so that they would not lose authority and the position that they had with the Arabs, where they would bring them gifts, and honor them. The cursed Jews feared that if they announced what they know about Muhammad ﷺ, then the people would abandon them and follow him. So they hid the truth so that they may retain the little that they were getting, and they sold their souls for this little profit. They preferred the little that they gained over guidance and following the truth, believing in the Messenger and having faith in what Allah was sent him with. Therefore, they have profited failure and loss in this life and the Hereafter.
Mentioned in the earlier verses were unlawful things which are tangible. Now, the verses that follow take up the intangible deeds that have been made unlawful. These are evil deeds, inner and outer. For instance, religious scholars among the Jews were addicted to giving out false verdicts in favour of people who bribed them. They would go to the limit of distorting the verses of the Torah to suit the desire of their client. In this, there is a veiled warning given to the ` ulama', the religious scholars of the community of the Last of the prophets, that they should keep away from such practices and never fall short in disclosing the true injunctions of Allah for any material reason or vested interest of their own.
When superstitious beliefs about prohibitions have been accepted by the masses as religious beliefs and held sacred, the religious scholars of the community fail to muster enough courage to declare openly that those beliefs have nothing to do with true religion, for they are afraid that if they did so, they would be severing themselves from the general public to whom they owe their popularity. They may revel in such compromises as bring them wealth and honour, but in the eyes of God, they are the worst offenders. Hiding the truth for worldly considerations is not one of those offences that God will ignore in the Hereafter. These are in fact crimes that deprive man of God’s mercy. Worse still are those, who, instead of accepting the truth when it is presented to them start engaging in meaningless discussions. They develop a propensity to divisiveness and ultimately they stray so far from the truth that there remains no chance of their returning.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.