Here's an interesting extract from Gur Pratap Granth by Kavi Santokh Singh Ji. One of the great pillars of Sikhism was always Guru Sahib's own Mehals, whether serving the hungry as Mata Kivi Ji through Langar or leading the Khalsa as Mata Sundri Ji.
Earlier on Kavi Ji also states that Guru Mother (most likely Mata Sundri Ji based on how Bhai Mani Singh Ji addressed her in his letters) also did Ardaas to take away all of Banda Singh Bahadur Ji's Spiritual Powers, and as per her Ardaas he lost control over them.