The Prohibition of hiding the Truth and distorting It with Falsehood
Allah forbade the Jews from intentionally distorting the truth with falsehood and from hiding the truth and spreading falsehood,
وَلَا تَلْبِسُواْ الْحَقَّ بِالْبَاطِلِ وَتَكْتُمُواْ الْحَقَّ وَأَنتُمْ تَعْلَمُونَ
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,
وَلَا تَلْبِسُواْ الْحَقَّ بِالْبَاطِلِ
(And mix not truth with falsehood) and said;
"Do not mix the truth with falsehood and the facts with lies."
Qatadah said that,
وَلَا تَلْبِسُواْ الْحَقَّ بِالْبَاطِلِ
(And mix not truth with falsehood) means,
"Do not mix Judaism and Christianity with Islam,
وَأَنتُمْ تَعْلَمُونَ
(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,
وَتَكْتُمُواْ الْحَقَّ وَأَنتُمْ تَعْلَمُونَ
(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."
وَأَقِيمُواْ الصَّلَةَ وَاتُواْ الزَّكَاةَ وَارْكَعُواْ مَعَ الرَّاكِعِينَ