Al Isra’ Ayah 59

وَمَا مَنَعَنَآ أَن نُّرْسِلَ بِٱلْأَيَـٰتِ إِلَّآ أَن كَذَّبَ بِهَا ٱلْأَوَّلُونَ‌ۚ وَءَاتَيْنَا ثَمُودَ ٱلنَّاقَةَ مُبْصِرَةً فَظَلَمُواْ بِهَا‌ۚ وَمَا نُرْسِلُ بِٱلْأَيَـٰتِ إِلَّا تَخْوِيفًا ٥٩ Nothing keeps Us from sending the ?demanded? signs except that they had ?already? been denied by earlier peoples. And We gave Thamûd the she-camel as a clear sign, but they wrongfully rejected it. We only send the signs as a warning.