Saqalain means Jinn and Humans…Hence, because Sayyidi Ghauth al-A`zam was the successor or the Na`ib of The Holy Prophet Sallallahu `alaihi wa sallam who was “Sayyid al-Thaqalain” as mentioned in the Durood-e-Taj, thus Sayyidi Gauth al-A`zam has also this magnificient maqam over humans and jinn as he is the na`ib of the Holy Prophet sallallahu `alaihi wa sallam, as he states in his famous Qaseedah al-Gauthiyyah:

wa kullu walliyyin `ala qadamin
wa ana `ala qadami Badr al-Kamali
wallahu a`lam bis sawaab
[Answer provided by:Mowlana Muhammed Kalim]