Quran 4:94 from Surah An-Nisaa on Divine Marvels.
يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوٓاْ إِذَا ضَرَبۡتُمۡ فِي سَبِيلِ ٱللَّهِ فَتَبَيَّنُواْ وَلَا تَقُولُواْ لِمَنۡ أَلۡقَىٰٓ إِلَيۡكُمُ ٱلسَّلَٰمَ لَسۡتَ مُؤۡمِنٗا تَبۡتَغُونَ عَرَضَ ٱلۡحَيَوٰةِ ٱلدُّنۡيَا فَعِندَ ٱللَّهِ مَغَانِمُ كَثِيرَةٞۚ كَذَٰلِكَ كُنتُم مِّن قَبۡلُ فَمَنَّ ٱللَّهُ عَلَيۡكُمۡ فَتَبَيَّنُوٓاْۚ إِنَّ ٱللَّهَ كَانَ بِمَا تَعۡمَلُونَ خَبِيرٗا
English translation: O you who believe[d] When you go forth in (the) way (of) Allah then investigate and (do) not say to (the one) who offers to you (a greeting of) peace You are not a believer seeking transitory gains (of) the life (of) the world for with Allah (are) booties abundant Like that you were from before then conferred favor Allah upon you so investigate Indeed Allah is of what you do All-Aware
Transliteration: yaayyuha alladhina amanu idha darabtum fi sabili al-lahi fatabayyanu wala taqulu liman alqa ilaykumu al-salama lasta mu'minan tabtaghuna arada al-hayati al-dun'ya fa'inda al-lahi maghanimu kathiratun kadhalika kuntum min qablu famanna al-lahu alaykum fatabayyanu inna al-laha kana bima ta'maluna khabiran