Your Holy Shock, Flash of Light, and Holy Light spells extend the duration of Tyr's Deliverance on yourself when cast on targets affected by Tyr's Deliverance.
Holy Shock: Extends 2 sec.
Flash of Light: Extends 4 sec.
Holy Light: Extends 8 sec.
Tyr's Deliverance can be extended up to a maximum of 40 sec.