I came across the comments below from Qadi Thanaullah al-Uthmani in his Tafsir al-Mazhari (8/320). The author whilst discussing the interpretation of verse 23 of Surah al-Shura discussed the virtues of the Noble Ahl al-Bayt, and towards the end of a lengthy discussion mentioned the following which might be of interest to readers:
“And from this I say that the the more preferable interpretation of the verse ‘I do not ask you for a wage..’ is except that you show love to my close relatives, household and family. This is because he (Allah bless him and give him peace) was the seal of the Prophets, and there is no Prophet after him. Rather the scholars of his community from the people of outward and inward knolwedge were placed to call towards Allah after him (Allah bless him and give him peace). Due to this Allah (Most High) ordered His Prophet (Allah bless him and give him peace) to order his community to show love to his household (Ahl al-Bayt) because Ali (Allah be pleased him) and the Imams from his offspring were the Poles (Aqtab) of the perfection of sainthood (wilayah). It was due to this that the Messenger of Allah (Allah bless him and give him peace) said ‘I am the city of knowledge and Ali is it’s door’ which was reported by al-Bazzar, al-Tabarani from Jabir and it has supporting narrations from the hadith of Ibn Umar, Ibn Abbas, Ali and his brother, and was graded Sahih by al-Hakim.
And it is due to this that you see that many of the spiritual orders (salasil) of the Shaykhs link back to the Imams of the Ahl al-Bayt, and that many of the Friends of Allah (awliyah) have been from the great Sayyids. Amongst them being the Ghawth al-Thaqalayn: Shaykh Muhiyuddin Abd al-Qadir al-Jili al-Hasani al-Hussaini, Baha al-Din al-Naqshabandi, Sayyid al-Sanad Mawdud al-Chishti, Sayyid Mueen al-Din al-Chishti, Abul Hasan al-Shadhili and others. Due to this the Messenger of Allah (Allah bless him and give him peace) said ‘I have left amongst you two weighty things, the Book of Allah and my family’.”