And We refrain from sending the signs, only because the men of former generations treated them as false: We sent the she-camel to the Thamud to open their eyes, but they treated her wrongfully: We only send the Signs by way of terror (and warning from evil).
And nothing has prevented Us from sending signs except that the former peoples denied them. And We gave Thamud the she-camel as a visible sign, but they wronged her. And We send not the signs except as a warning.