Companions in the Quran
The word Sahabi (Companion) is derived from the same root as the words "suhbah" (talk/conversation) and "sahib" (owner). A person who saw the Messenger of Allah as a believer and died as a believer is called a "Companion" (Sahabi). Sahaba and ashab are the plural form of sahabi. This word is also used in the form of Sahaba al-Kiram or Ashab al-Ghuzin meaning good and distinguished people.
The divine books, primarily the Quran, praised the Companions and mentioned their superior qualities.
There are several verses that praise and appreciate them in the Quran. Some of them are as follows:
“Muhammad is the Messenger of Allah; and those who are with him are strong against Unbelievers, (but) compassionate amongst each other. Thou wilt see them bow and prostrate themselves (in prayer) seeking Grace from Allah and (His) Good Pleasure. On their faces are their marks, (being) the traces of their prostration. This is their similitude in the Towrah; and their similitude in the Gospel is: like a seed which sends forth its blade, then makes it strong; it then becomes thick and it stands on its own stem (filling) the sowers with wonder and delight. As a result, it fills the Unbelievers with rage at him. Allah has promised those among them who believe and do righteous deeds Forgiveness and a great Reward.” 
In the following verse, their praised properties are mentioned:
“Those who believe, and adopt exile, and fight for the Faith in the Cause of Allah, as well as those who give (them) asylum and aid― these are (all) in very truth the Believers: for them is the forgiveness of sins and a provision most generous.” 
It is stated as follows that they attained the consent and pleasure of Allah:
“The vanguard (of Islam)― the first of those who forsook (their homes) and of those who gave them aid, and (also) those who follow them in (all) good deeds― well― pleased is Allah with them, as are they with Him: for them hath He prepared Gardens under which rivers flow, to dwell therein forever: that is the Supreme Felicity.” 
The bonds of brotherhood of Muhajirs and Ansar are expressed as follows:
“Some part is due) to the indigent Muhajirs, those who were expelled from their homes and their property while seeking Grace from Allah and (His) Good pleasure, and aiding Allah and His Messenger: such are indeed the sincere ones―
And those who before them, had homes (in Medina) and had adopted the Faith― show their affection to such as came to them for refuge, and entertain no desire in their hearts for things given to the (latter), but give them preference over themselves even though poverty was their (own lot). And those saved from the covetousness of their own souls, they are the ones that achieve prosperity.
And those who came after them say: "Our Lord! Forgive us, and our brethren who came before us into the Faith and leave not in our hearts, rancor (or sense of injury) against those who have believed Our Lord! Thou art indeed Full of Kindness, Most Merciful.” 
The courage of the Companions is narrated as follows:
“Men said to them: "A great army is gathering against you, so fear them": but it (only) increased their Faith. They said: "For us Allah sufficeth, and He is the best disposer of affairs.” 
In the other divine books, the Companions are mentioned with praise. The following is stated about them in Psalms: “O David (Dawud)! I rendered Muhammad and his ummah superior to all ummahs.”  In the Old Testament, the Companions are mentioned as "the holy people" and in the New Testament as "people appointed for jihad".
When Hz. Kab was asked about what is stated in the Bible about Companions, he said,
“Ahmad and his ummah praise Allah a lot. They never give up thanking Him whether they feel good or bad. They praise Allah and mention His name everywhere. Their supplication rises to the sky. They perform prayers in such awe that the humming they produce is similar to the humming of the bees on rocks. They form ranks like angels in prayers. When they fight in the way of Allah, angels are located in front of and behind them with their sharp and pointed spears and Allah gives them shade just as these white flowers follow the shade of their leaves - pointing to them with his index finger.” 
 al-Fath, 29.
 al-Anfal, 74.
 at-Tawba, 100.
 al-Hashr, 8-10.
 Aal-i Imran, 173.
 al-Bidaya, 2: 326.
 Hilyatu’l-Awliya, 5: 386.