It is those who believe and confuse not their belief with Zulm (wrong), for them (only) there is security and they are the guided.Therefore, those who worship Allah alone without partners, will acquire safety on the Day of Resurrection, and they are the guided ones in this life and the Hereafter.Shirk is the Greatest Zulm (Wrong) Al-Bukhari recorded that Abdullah said,"When the Ayah, وَلَمْ يَلْبِسُواْ إِيمَانَهُم بِظُلْمٍ (and confuse not their belief with Zulm (wrong)) was revealed, the Companions of the Prophet said, `And who among us did not commit Zulm against himself?' The Ayah, إِنَّ الشِّرْكَ لَظُلْمٌ عَظِيمٌ (Verily! Joining others in worship with Allah is a great Zulm (wrong) indeed) (31:13), was later revealed."Imam Ahmad recorded that Abdullah said,"When this Ayah was revealed, الَّذِينَ امَنُواْ وَلَمْ يَلْبِسُواْ إِيمَانَهُم بِظُلْمٍ (It is those who believe and confuse not their belief with Zulm (wrong)), it was hard on the people. They said, `O Allah's Messenger! Who among us did not commit Zulm against himself?'He said,إِنَّهُ لَيْسَ الَّذِي تَعْنُونَ أَلَمْ تَسْمَعُوا مَا قَالَ الْعَبْدُ الصَّالِحُIt is not what you understood from it. Did you not hear what the righteous servant (Luqman) said, يَا بُنَيَّ لَاا تُشْرِكْ بِاللَّهِ إِنَّ الشِّرْكَ لَظُلْمٌ عَظِيمٌ (O my son! Join not in worship others with Allah. Verily! Shirk is a great Zulm (wrong) indeed). (31:13), Therefore, it is about Shirk.Allah's statement