Be Cautious of Discrimination

[Surah 4: Ayah 94]: O you who believe! When you go (to fight) in the cause of Allah, verify (the truth), and say not to anyone who greets you: "You are not a believer;'' seeking the perishable goods of the worldly life. There is much more benefit with Allah. Even as he is now, so were you yourselves before, till Allah conferred on you His Favors, therefore, be cautious in discrimination. Allah is Ever Well-Aware of what you do.

Imam Ahmad (rahimahUllaah) recorded that `Ikrimah said that Ibn `Abbas said, "A man from Bani Sulaym, who was tending a flock of sheep, passed by some of the Companions of the Prophet (radhiAllaahu 'anhum) and said Salam to them. They said (to each other), `He only said Salam to protect himself from us.' Then they attacked him and killed him. They brought his sheep to the Prophet (sallAllaahu 'alayhi wa sallam), and this Ayah was revealed,

(O you who believe!), until the end of the Ayah.'' At-Tirmidhi recorded this in his (chapter on) Tafsir, and said, "This Hadith is Hasan, and it is also reported from Usamah bin Zayd.'' Al-Hakim also recorded it and said, "Its chain is Sahih, but they did not collect it.'' Al-Bukhari recorded that Ibn `Abbas commented;

(and say not to anyone who greets you: "You are not a believer;''), "A man was tending his sheep and the Muslims caught up with him. He said, `As-Salamu `Alaykum.' However, they killed him and took his sheep. Allah revealed the Ayah;

"And say not to anyone who greets you: "You are not a believer; seeking the perishable goods of the worldly life.'' Ibn `Abbas (rahimahUllaah) said; "The goods of this world were those sheep.'' 

- Tafseer Ibn Kathir