There is no one more deviated before Allah than the one who rejects the Divine Proof (peace be upon him)

عَنِ الْمُعَلَّى بْنِ خُنَيْسٍ عَنْ اَبِي عَبْدِ اللهِ ع‏ فِي قَوْلِ اللهِ عَزَّ وَ جَلَ‏ وَ مَنْ اَضَلُّ مِمَّنِ اتَّبَعَ هَواهُ بِغَيْرِ هُدىً‏ مِنَ‏ اللهِ‏ يَعْنِي‏ مَنْ‏ يَتَّخِذُ دِينَهُ‏ رَأْيَهُ‏ بِغَيْرِ هُدَى اَئِمَّةٍ مِنْ اَئِمَّةِ الْهُدَى.

Mualla Ibn Khunais reports from Imam Abu Abdillah [al-Sadeq a.s.] concerning the word of Allah – Mighty and Majestic be He – “And who is more deviated than the one who follows his carnal desires instead of guidance from Allah” means “Whoever takes his religion whimsically without a guided Imam from the Imams of guidance (i.e. an Imam appointed by Allah.”

Note

This narration emphasizes the importance of following a guided Imam for proper understanding of religion.

Reference

1. Basaaer al-Darajaat, vol. 1, p. 13, H. 1
2. Al-Burhan fee Tafseer al-Quran, vol. 4, p. 271, H. 8137
3. Behaar al-Anwaar, vol. 2, p. 302, H. 35