A yellow prayer card with Mary painted on its front.
Upon activation, Isaac gains an Eternal Heart. If you already have an Eternal Heart, you will gain a new heart container upon activation.
If the player gains 7 health increase upgrades from Eternal Hearts in a single playthrough, the player will be awarded with an upgrade called "Eternal Life" (This is the name that appears in-game). The character will turn white and gain flight, and additionally higher attack speed and damage. (Only in Binding of Isaac Eternal Edition)
Although you cannot gain more than twelve hearts through the use of this card outside of the Eternal Edition, it is still a viable line of defense at maximum health as additional Eternal Hearts can still be gained.
- Habit - Heart Containers will be added much quicker if Isaac takes damage. In addition to having the Habit, having either or both of The Wafer/Scapular, or The Battery/9V combos leads to technically infinite heart containers in the Eternal Edition. Though the red heart containers are capped at 12 outside of the Eternal Edition, when used in addition with Guppy's Paw, the player can create a ridiculous amount of souls hearts on one floor by swapping the two items. This could also effectively remove the need for the Scapular.
- This item represents a holy card: a small, mass-produced devotional image similar in size to a baseball card, with a simple reproduction of a holy icon printed on one side and often a short prayer printed on the opposite side, they are meant to be carried with a believer or situated in a familiar place and act as a focus for prayer and devotion in everyday life.
- Even though the Prayer Card is marked as a "Special Item" in the game's code, it is not actually a special item.