Pray for a miracle

[Viperlocc]

Pray for a Miracle. At any time, even during combat, you
may discard two cards, from your hand OR the table, to take the top
card from the Treasure deck face-down into your hand.

My question is that is there a limit to the amount of times a Cleric can do this?

Only asking because lets say the Cleric is doing this to stop someone from winning the game and he goes until he is almost ouf of cards and player 2 then says (who also isnt in the combat) I will give you 20 items for your 1 there which in turn gives the Cleric more time to hopefully find a good stopping card.