Wa law shaaa'al laahu laja'alakum ummmatanw waahidatanw wa laakiny yudillu many-yashaaa'u wa yahdee many-yashaaa'; wa latus'alunna 'ammaa kuntum ta'maloon
And if Allah please He would certainly make you a single nation, but He causes to err whom He pleases and guides whom He pleases; and most certainly you will be questioned as to what you did.