يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوٓاْ إِذَا ضَرَبۡتُمۡ فِى سَبِيلِ ٱللَّهِ فَتَبَيَّنُواْ وَلَا تَقُولُواْ لِمَنۡ أَلۡقَىٰٓ إِلَيۡكُمُ ٱلسَّلَٰمَ لَسۡتَ مُؤۡمِنًا تَبۡتَغُونَ عَرَضَ ٱلۡحَيَوٰةِ ٱلدُّنۡيَا فَعِندَ ٱللَّهِ مَغَانِمُ كَثِيرَةٌ ۚ كَذَٰلِكَ كُنتُم مِّن قَبۡلُ فَمَنَّ ٱللَّهُ عَلَيۡكُمۡ فَتَبَيَّنُوٓاْ ۚ إِنَّ ٱللَّهَ كَانَ بِمَا تَعۡمَلُونَ خَبِيرًا
O ye who believe! When ye go abroad in the cause of Allah, investigate carefully, and say not to any one who offers you a salutation: "Thou art none of a believer!" Coveting the perishable goods of this life: with Allah are profits and spoils abundant. Even thus were ye yourselves before, till Allah conferred on you His favours: Therefore carefully investigate. For Allah is well aware of all that ye do.<br/>
The following was revealed when a group from among the Companions passed by a man from the Banoo Sulaym driving his flock of sheep, and he offered them a greeting of peace. But they said, 'He only greeted us dissimulating, out of fear'. So they killed him and took away his flock: O you who believe, when you are going forth, travelling in order to struggle, in the way of God, be discriminating (fa-tabayyanoo; a variant reading has fa-tathabbatoo, 'ascertain', here and further below); and do not say to him who offers you peace (read al-salaam or al-salam), that is, the greeting, or [offers you] submission, declaring the profession of faith (shahaada), which is an indication of being a Muslim: 'You are not a believer: you are only saying this to dissimulate for fear of your life and property', so that you then end up killing him, desiring, seeking by this, the transient goods of the life of this world, that is, its enjoyment, in the way of spoils. With God are plenteous spoils, rendering you free of the need to kill such a person for his property. So you were formerly, when your lives and property were protected simply upon your professing the faith; but God has been gracious to you, making you known for your faith and uprightness. So be discriminating, lest you kill a believer and treat those entering the religion as you were treated [formerly]. Surely God is ever Aware of what you do, and will requite you for it.