Evidence from the Statements of the Companions of the Prophet Muhammad (peace be upon him)
Muslims believe that no one understood Allah and His Messenger better than the companions of the Prophet peace be upon him. The companions of the Prophet peace be upon him were promised paradise in the Qur'an...
والسابقون الاولون من المهاجرين والانصار والذين اتبعوهم باحسان رضي الله عنهم ورضوا عنه واعد لهم جنات تجري تحتها الانهار خالدين فيها ابدا ذلك الفوز العظيم
And (as for) the foremost, the first of the Muhajirs and the Ansars, and those who followed them in goodness, Allah is well pleased with them and they are well pleased with Him, and He has prepared for them gardens beneath which rivers flow, to abide in them forever; that is the mighty achievement.
The Muhajirs refer to the companions of the Prophet peace be upon him that migrated to Madina. The Ansar refer to those Muslims in Medina that welcomed the Muhajirs to come to their city.
The Prophet Muhammad (peace be upon him) also said:
"Indeed the people of the Book before you split into seventy-two sects. And this nation will split into seventy-three sects, seventy-two are in the Fire and one in Paradise". And in another narration, "All are in the Fire except one." It was asked: Who is that one? He replied, "That which I and my Companions are upon" (Related by at-Tirmidhi (5/62) and al-Haakim (1/128). It has been authenticated by al-Haafidh al-Iraaqee in Takhreejul-Ihyaa (3/199) and al-Albaanee in as-Saheehah (here)
So here we see that Islam teaches that the companions of the Prophet peace be upon him are the saved sect and were promised paradise. This is clearly because they understood and practiced Islam better than anyone else. They are a great authority to refer to. Obviously, this does not mean that the companions were individually infallible, however their consensus on a matter is.
Here, we will see some of the perspectives of the companions of the Prophet peace be upon him towards to the Christian and Jewish scriptures.