The distinction between those with receptive hearts and those with sealed hearts

قُلِ ٱنظُرُوا۟ مَاذَا فِى ٱلسَّمَـٰوَٰتِ وَٱلْأَرْضِ ۚ وَمَا تُغْنِى ٱلْـَٔايَـٰتُ وَٱلنُّذُرُ عَن قَوْمٍ لَّا يُؤْمِنُونَ

Say, "Observe what is in the heavens and the earth." But of no avail will be signs or warners to a people who do not believe.