Al-An-Am 6:125 فمن يرد الله ان يهديه يشرح صدره للاسلام ومن يرد ان يضله يجعل صدره ضيقا حرجا كانما يصعد في السماء كذالك يجعل الله الرجس على الذين لا يومنون ١٢٥

Those whom Allah (in His plan) willeth to guide,- He openeth their breast to Islam; those whom He willeth to leave straying,- He maketh their breast close and constricted, as if they had to climb up to the skies: thus doth Allah (heap) the penalty on those who refuse to believe.