I have a weapon for your cleric
The Mace of the "Prophet"
(please note: I don't know your cleric or the god/ess worshiped by said cleric, so please feel free to "massage" this as needed to make it fit).
A very long time ago, the Prophet walked the earth, dispensing the wisdom of the God/ess and fighting evil with his trice-blessed mace. Upon his death, the prophet and his/her belongings disappeared. This was well over 1000 years ago.
However, 800 years ago, the mace resurfaced. The mace had been found in a high mountain pass by an explorer named Somterif,, who demanded an outrageous quantity of gold for the mace's return. The clergy, eager to get their hands on the mace, paid the sum.
Sadly, the mace was *not* the mace of the Prophet but a very clever forgery, crafted by Somterif, who was a capable enchanter and skilled researcher. The mace he produced was a fairly potent magical weapon created at high cost... but still a fake, and not worth the fortune he was paid. Somterif retired and enjoyed the spoils of his con.
Unfortunately for Somterif, it is *far* harder to fool a god/ess than a clergy. Upon his death, the god/ess decided to punish Somterif (who had no patron god to speak for him) and trapped his soul inside the mace, which had become a symbol of the faith. The god/ess explained to Somterif that he was to provide the wielder of the mace with sound advice and magical boons. But Somterif had to beware - should it ever be discovered that he was *not* the soul of a saint but that of a con-man, the faith in the mace would be shattered, and the mace would be locked away by the clergy forever... with Somterif trapped inside, in the dark...
The mace of the prophet was lost 50 years ago. The party may find it by chance, or be sent on a quest to retrieve it.
The Mace of the "Prophet" has Int 14, cha 12 and wis 10. His hearing/sight is limited to 30 feet, and he communicates by voice. Somterif started as Chaotic neutral but has been slowly moving towards the god/ess appropriate alignment. It is a +2 mace (or other "church-appropriate" weapon). Somterif can cast, through it, 3 spells/day (1 level 1, 1 level 2, 1 level 3), which are wizard spells that would "fit" for the particular church of the Prophet (if this is a fire god, then firewall it is!).
Somterif's main interest is *not being lost* and *not being discovered as a fake*. He has just spent 50 years isolated in a cave or something and has no interest in doing so again, no sir! He will provide what his best guess of "wise advice" is. He has been serving priests and paladins of the church for some times, so he knows how to "speak the lingo" so to speak, but his advice will sound far wiser than it actually is. Rarely, Somterif will "slip" and propose a devious/cunning plan as a solution to a problem, but if called on it will spout some religious platitude to justify it such as "a fooled opponent can still be made to see the light, a slain opponent cannot".