khātam al-awliya etc.
خاتم النبيين title given to Muḥammad ﷺ in 33:40.
A seal does two things:
- it closes a package so no intermediary can meddle, tamper with the contents
- it authenticates, confirms, prooves a document as coming from the authority, sender
Muḥammad ﷺ confirmed our religion in its final form.