The purpose of signs as warnings, not mere proofs

وَمَا مَنَعَنَآ أَن نُّرْسِلَ بِٱلْـَٔايَـٰتِ إِلَّآ أَن كَذَّبَ بِهَا ٱلْأَوَّلُونَ ۚ وَءَاتَيْنَا ثَمُودَ ٱلنَّاقَةَ مُبْصِرَةً فَظَلَمُوا۟ بِهَا ۚ وَمَا نُرْسِلُ بِٱلْـَٔايَـٰتِ إِلَّا تَخْوِيفًا

And nothing has prevented Us from sending signs [i.e., miracles] except that the former peoples denied them. And We gave Thamūd the she-camel as a visible sign, but they wronged her. And We send not the signs except as a warning.