All perfect praise be to Allah. Blessings and peace be upon our Prophet Mohammad.
The Sahaba are the best people after the Prophets, and all of them are Honorable, so it is impermissible to impeach, or belittle them for they are the crème de la crème. Almighty Allah said: “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 God with them, as are they with Him: for them hath He prepared gardens under which rivers flow, to dwell therein for ever: that is the supreme felicity.” {At-Tawbah/100}. The Prophet{PBUH} said: “Do not abuse my companions for if any one of you spent gold equal to Uhud (in Allah's Cause) it would not be equal to a Mud or even a half Mud spent by one of them."{Bukhari}.
Ibn Msoud reported : “ Almighty Allah knows that Mohammad`s heart is the purest of all man-kind, so He made him a Prophet. He also knows that the Sahabah come second as regards the purity of their hearts, so He made them the Prophet`s companions. Their hearts follow natural disposition, so whatever they view as good is good, and whatever they view as bad is bad.” {Ahmad}.
The people of Sunnah have agreed that it is unlawful to impeach any of the Sahaba on basis of the disagreement that had occurred amongst them due to their Ijtihad (a juristic opinion on matters which are not specified in the Quran and Sunnah). Almighty Allah has forgiven the one who errs in his Ijtihad; rather, it is proven that such a person receives one reward when he is wrong and two rewards when he is right.
Therefore, a Muslim must follow the guidance of the Sahabah in matters of belief, faith, manners of worship and other matters, and mustn’t favor between them, or revile any of them. It is more suitable for a Muslim to busy himself/herself with pleasing Almighty Allah and abstain from arguing matters that are of no use to him/her. And Allah knows best.