Allah forbade the Jews from intentionally distorting the truth with falsehood and from hiding the truth and spreading falsehood,
(And mix not truth with falsehood, nor conceal the truth while you know (the truth)).
So Allah forbade them from two things; He ordered them to make the truth known, as well as explaining it. Ad-Dahhak said that Ibn `Abbas mentioned the Ayah,
(And mix not truth with falsehood) and said; "Do not mix the truth with falsehood and the facts with lies." Qatadah said that,
(And mix not truth with falsehood) means, "Do not mix Judaism and Christianity with Islam,
(while you know (the truth).) that the religion of Allah is Islam, and that Judaism and Christianity are innovations that did not come from Allah." It was reported that Al-Hasan Al-Basri said similarly.
Also, Muhammad bin Ishaq narrated that Ibn `Abbas said that,
(nor conceal the truth while you know (the truth).) means, "Do not hide the knowledge that you have of My Messenger and what he was sent with. His description, which you know about, can be found written in the Books that you have."
It is possible that it means, "..although you know the tremendous harm that this evil will cause people, misguiding them and leading them to the Fire, because they will follow the falsehood that you mixed with the truth in your claims."
(And perform As-Salat and give Zakah, and bow down along with Ar-Raki`in.)
Muqatil said, "Allah's statement to the People of the Book,
(And perform As-Salah) commands them to perform the prayer behind the Prophet ,
(and give Zakah) commands them to pay the Zakah to the Prophet , and
(and bow down along with Ar-Raki`in) commands them to bow down with those who bow down among the Ummah of Muhammad . Allah therefore commands the People of the Book to be with, and among the Ummah of Muhammad ." In addition, Allah's statement,
(And bow down along with Ar-Raki`in) means, "And be among the believers performing the best deeds they perform, such as, and foremost, the prayer." Many scholars said that this Ayah (2:43) is proof for the obligation of performing the prayer in congregation (for men only). I will explain this ruling in detail in Kitab Al-Ahkam Al-Kabir, Allah willing.