Pray

is, unfortunately, rarely worth taking. The issue with Pray is that it does literally nothing on the turn you cast it, unless you're entering Divinity. Additionally, because you had to draw Pray, then draw the , just to draw 2 cards, the end result is that you didn't draw any cards. This makes Pray one of the worst cards in the game for a normal deck, unless you're incredibly committed to achieving Divinity. However, if you can assemble a small enough deck (less than 9 cards) that can somehow generate a lot of energy, a Pray+ can essentially re-draw itself and an Insight over and over.
Ultimately, one of the best ways to consider Divinity cards is to consider how many cycles through your deck it takes to achieve Divinity. For example, a card that gives 3 mantra takes 4 deck cycles to reach Divinity, while a card that gives 4 mantra would take 3 deck cycles. Thus, you should ultimately achieve to have your mantra cards give a total of either 5 or 10 mantra each deck cycle. and can also help with this. As an example of a great Divinity deck, a deck with an upgraded , a , and a can easily achieve 10 Mantra in just 2-3 turns.