What is the meaning of "Is one whose heart Allah has expanded to Islam and is thereby upon light from his Lord, like one who is not? So woe to those whose hearts are hardened against the remembrance of Allah. Those are in manifest error. Allah has sent down the best statement: a Book consistent and oftentimes repeated, from which shiver the skins of those who fear their Lord. Then their skins and their hearts soften to the remembrance of Allah"?

The meaning of the verses is that God informed that whoever opens his heart to His knowledge and acknowledges His Oneness, and submits to His obedience, is upon insight and certainty from his Lord, following His command, and refraining from what He has forbidden him. And this is not equal to a hardened heart. Then God praised the Quran by saying: "God has sent down the best of statements: a Book consistent and oft-repeated" (39:23). This means that the Quran is consistent, with parts resembling each other. Then, He mentioned the characteristic of the righteous whose skins shiver and hearts humble when hearing the Quran, then soften at the mention of God, hoping for His mercy.