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.