We find in al Bidaya wa al Nihaya, 2/133

وقال الإمام أحمد حدثنا شريح بن النعمان حدثنا هشيم أنبأنا مجالد عن الشعبي عن جابر بن عبدالله أن عمر بن الخطاب أتى النبي صلى الله عليه و سلم بكتاب أصابه من بعض أهل الكتاب فقرأه على النبي صلى الله عليه و سلم قال فغضب وقال امتهوكون فيها يا ابن الخطاب والذي نفسي به لقد جئتكم به بيضاء نقية لا تسألوهم عن شيء فيخبروكم بحق فتكذبوا به أو بباطل فتصدقوا به والذي نفسي به لو أن موسى كان حيا ما وسعه الا أن يتبعني تفرد به أحمد واسناده على شرط مسلم

Jabir bin Abdullah narrates that Umar came to Holy Prophet (asws) with some books He got from Ahlul Kitab; and recited it in front of Holy Prophet (asws). Jabir says: Holy Prophet (asws) got angry and said:

You have doubts o Son of Khitab; By the One who holds my life in His Hand, I came to you with crystal clear teachings. Do not ask them (Ahlul Kitab) for they may tell you something true, and you may deny it; or they may tell you something false, and You may accept it. By the One who holds my life! If Moses was alive, He would have followed me.

Narrated only by Ahmad and Chain is Authentic on terms set by Imam Muslim

Similar narration has also been authenticated as HASAN/Good by Sheikh AlBany in Zilal ul Jannah, 1/21, narration 50