In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Allaah [The Mighty and Majestic] said:
إِنَّ إِبْرَاهِيمَ كَانَ أُمَّةً قَانِتًا لِّلَّهِ حَنِيفًا وَلَمْ يَكُ مِنَ الْمُشْرِكِينَ
Verily, Ibraaheem was an Ummah [leader], Qaanitan [obedient], Haneefan [one who worshipped Allaah alone], and he was not one of the Mushrikeen [polytheists and those who associate partners with Allah in worship]. [Surah An-Nahl. Aayah 120]
Ibraaheem [alayhis salaam] is the Imaam of the Hunafaa [i.e. Leader of the people of Tawheed- those who single out Allaah in worship] and this is why Allaah said to him: [إِنِّي جَاعِلُكَ لِلنَّاسِ إِمَامًا – Verily, I am going to make you a leader (Prophet) of humankind]. [Surah Al-Baqarah. Aayah 124].
It is a customary habit of the people that they do attach themselves to the great personalities, especially those whom they hold in high esteem. Therefore, if a person utilise as proof that the one he follows is an Imaam [An Upright Leader], then there is no Imaam [for humankind] greater than Prophet Ibraaheem [i.e. after Prophet Muhammad], and Allaah [The Mighty and Majestic] stated about Prophet Ibraaheem: [وَمَن يَرْغَبُ عَن مِّلَّةِ إِبْرَاهِيمَ إِلَّا مَن سَفِهَ نَفْسَهُ – And who turns away from the religion of Ibraaheem (i.e. Islamic Monotheism) except him who befools himself?] [Surah Al-Baqarah. Aayah 130]
If a person addresses someone else with the statement, ‘My Shaikh’ in connection to a Soofee Tareeqah [i.e. a Soofee Path] or in connection to affairs of misguidance in the name of following someone he considers an Imaam [Upright Leader], then indeed Prophet Ibraaheem is the Imaam of the people who worship Allaah alone [i.e. the greatest Imaam of Tawheed and perfect example after Prophet Muhammad]. If a person utilises this as his proof [i.e. that the one he follows is an Imaam], then examine the Aqeedah [Islamic Creed] of this person whom he gives the status of Imaam and judge it based on the Qur’aan to establish whether he is from the people of Tawheed. If a person seeks to use the station of Imaam as proof, then indeed this should be the proof [i.e. examine the Aqeedah of the one given the status of Imaam and judge it based on the Qur’aan and the authentic Sunnah to establish whether he is a person upon Tawheed]. Also, Allaah [The Mighty and Majestic] said about the Prophet [sallal laahu alayhi wasallam]:
لَّقَدۡ كَانَ لَكُمۡ فِى رَسُولِ ٱللَّهِ أُسۡوَةٌ حَسَنَةٌ۬ لِّمَن كَانَ يَرۡجُواْ ٱللَّهَ وَٱلۡيَوۡمَ ٱلۡأَخِرَ وَذَكَرَ ٱللَّهَ كَثِيرً۬ا
Indeed in the Messenger of Allah (Muhammad) you have a good example to follow for him who hopes in (the Meeting with) Allah and the Last Day and remembers Allah much. [Surah Al-Ahzaab. Aayah 21]
An Excerpt from ‘Sharh Kitaab At-Tawheed’. Lesson 1- By Shaikh Abdur Razzaaq Al-Badr [hafidhahullaah]. Slightly paraphrased