Does this also mean you can't cast Shield of Faith, and then later on cast Hammer of Sigmar (i.e have them both going at once)? Or even have Shield, Hammer, Hearts of Steel and Armour of Righteousness all going at once.
There are two ways that I interpret Da Bank's answer. The first is that the only one instance of the SAME prayer / spell may be in effect any time unless it says otherwise. The second is taking what he said more literally that only one prayer / spell may be in effect any time unless the prayer / spell says otherwise. I'm inclined to lean towards the first interpretation as being what Da Bank was meaning (I know that he'll correct me if I'm wrong).
The rules for Shield of Faith and Hearts of Steal both explicitly mention when they end which is beyond a single turn. Armour of Righteousness says that it only lasts until the beginning of the Priest's next shooting phase and therefore the prayer must be recast to keep it active. I would think that if the other two prayers are already active then Armour of Righteousness could also be cast making three active prayers. The wording for Hammer of Sigmar was a bit ambiguous to me (hence my OP) because it said that the Priest "must test each shooting phase he wants to use the Hammer." I had wondered whether this wording implied that this "test" was different to recasting the prayer because otherwise I figured the wording would match Armour of Righteousness which must be recast each turn.
If the "test" is
not recasting the prayer then I do not see any issue with a scenario like this (based on my first interpretation of Da Bank's answer):
1] Cast Shield of Faith.
2] The Priest successfully roles a 1 or a 2 in his next recovery phase and so Shield of Faith remains active.
3] Cast Hearts of Steel.
4] The Priest successfully roles a 1 or a 2 in his next recovery phase and so Shield of Faith remains active. The Priest was also not knocked down, stunned or taken OOA and so Hearts of Steel remains active.
5] Cast Hammer of Sigmar.
6] The Priest successfully roles a 1 or a 2 in his next recovery phase and so Shield of Faith remains active. The Priest was also not knocked down, stunned or taken OOA and so Hearts of Steel remains active. The Priest also successfully passes the test in his shooting phase and so Hammer of Sigmar remains active.
7] Cast Armour of Righteousness.
8] The Priest successfully roles a 1 or a 2 in his next recovery phase and so Shield of Faith remains active. The Priest was also not knocked down, stunned or taken OOA and so Hearts of Steel remains active. The Priest also successfully passes the test in his shooting phase and so Hammer of Sigmar remains active.
9] Recast Armour of Righteousness.
On the other hand if the "test" for Hammer of Sigmar is simply recasting the prayer then steps 6 onwards mentioned above are incorrect and the maximum number of active prayers would be three as previously mentioned (Shield of Faith, Hearts of Steel and Armour of Righteousness
OR Shield of Faith, Hearts of Steel and Hammer of Sigmar
OR Shield of Faith, Hearts of Steel and Soulfire
OR Shield of Faith, Hearts of Steel and Healing Hands).