Tafsir of Qaf 50:33

من خشي الرحمن بالغيب

Who feared Ar-Rahman unseen, who feared Allah in secret when only Allah the Exalted and Most Honored could see him. The Prophet said,

ورجل ذكر الله تعالى خاليا ففاضت عيناه

And a man who remembered Allah the Exalted while alone, and his eyes became tearful. Allah said,

وجاء بقلب منيب

and brought a heart turned in repentance. meaning, he will meet Allah, the Exalted and Most Honored, on the Day of Resurrection with a heart turned in repentance to Him and absolutely free (of Shirk) and humbled to Him,