The Quran

وَيَقولُ الَّذينَ كَفَروا لَولا أُنزِلَ عَلَيهِ آيَةٌ مِن رَبِّهِ ۗ قُل إِنَّ اللَّهَ يُضِلُّ مَن يَشاءُ وَيَهدي إِلَيهِ مَن أَنابَ

Muhammad Asad

NOW THOSE who are bent on denying the truth [of the Prophet's message] say, "Why has no miraculous sign ever been bestowed upon him from on high by his Sustainer?"¹ Say: "Behold, God lets go astray him who wills [to go astray]², So just as He guides unto Himself all who turn unto Him -

See verse 7 of this surah and the corresponding note 16. The repetition of this question at this place points to its connection with the reference to "those who break their bond with God after it has been established [in their nature]" in verse 25 above (elucidated in note 19 on 2:27). The abandonment of their original, innate faculty to realize the existence of God and their own dependence on His guidance - caused by their utter immersion in the passing pleasures of this world's life - makes it impossible for "those who are bent on denying the truth" to sense the breath of the divine in the message propounded to them by Muhammad: and so they refuse to accept it as true unless it is supported by an outward "miracle". (See in this connection note 94 on 6:109.)
Or: "God lets go astray whomever He wills". Regarding the rendering adopted by me, see surah 14, note 4.