SURAH AL-BAQARAH: 37

Part 4

This verse also tells us that it is only Allah Ta'alah who has the authority to accept a person's Taubah (repentance) and forgive their sins. In some religions people mistakenly started believing that their religious leaders could forgive their sins on Allah's behalf. They would give them some money or do some rituals of repentance ordered by them, and believe that just because their religious leader said that they had forgiven their sins, Allah Ta'alah had also forgiven their sins. Some Muslims also started holding beliefs like this that their religious teacher, Pir, Alim or Murshid could forgive all their sins, or believed that by praying at a deceased saint's mausoleum they could have all their sins forgiven by that saint. The truth is that no human being has the authority to forgive sins, it is only Allah Ta'alah who has the authority to accept repentance and forgive someone's sins and, to Him alone we should pray for repentance (Taubah). Every saint, Alim and Murshid is himself dependent on Allah Ta'alah for his own sins to be forgiven.

From Ma'ariful Quran, by Mufti Muhammad Shafi RE