Guidance is granted to Those Who have Taqwa
Hidayah - correct guidance - is only granted to those who have Taqwa - fear of Allah. Allah said,
[قُلْ هُوَ لِلَّذِينَ ءَامَنُواْ هُدًى وَشِفَآءٌ وَالَّذِينَ لاَ يُؤْمِنُونَ فِى ءَاذَانِهِمْ وَقْرٌ وَهُوَ عَلَيْهِمْ عَمًى أُوْلَـئِكَ يُنَادَوْنَ مِن مَّكَانٍ بَعِيدٍ]
(Say: It is for those who believe, a guide and a healing. And as for those who disbelieve, there is heaviness (deafness) in their ears, and it (the Qur'an) is blindness for them. They are those who are called from a place far away (so they neither listen nor understand)) (41:44), and,
[وَنُنَزِّلُ مِنَ الْقُرْءَانِ مَا هُوَ شِفَآءٌ وَرَحْمَةٌ لِّلْمُؤْمِنِينَ وَلاَ يَزِيدُ الظَّـلِمِينَ إَلاَّ خَسَارًا ]
(And We send down of the Qur'an that which is a healing and a mercy to those who believe (in Islamic Monotheism and act on it), and it increases the Zalimin (wrongdoers) in nothing but loss) (17:82).
This is a sample of the numerous Ayat indicating that the believers, in particular, benefit from the Qur'an. That is because the Qur'an is itself a form of guidance, but the guidance in it is only granted to the righteous, just as Allah said,
[يَأَيُّهَا النَّاسُ قَدْ جَآءَتْكُمْ مَّوْعِظَةٌ مَّن رَّبِّكُمْ وَشِفَآءٌ لِّمَا فِى الصُّدُورِ وَهُدًى وَرَحْمَةٌ لِّلْمُؤْمِنِينَ ]
(O mankind! There has come to you a good advice from your Lord (i. e. the Qur'an, enjoining all that is good and forbidding all that is evil), and a healing for that (disease of ignorance, doubt, hypocrisy and differences) which is in your breasts, ـ a guidance and a mercy (explaining lawful and unlawful things) for the believers) (10:57).
Ibn `Abbas and Ibn Mas`ud and other Companions of the Messenger of Allah said,
(guidance for the Muttaqin (the pious and righteous persons), means, a light for those who have Taqwa.