Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: "You gotta pray if you want Santa to bring you Christmas presents!" "I know (いの), I know," you reply as you begin to pray to Santa. You should say this out loud to remember it better.
I prayed for the hurricane victims.
I will pray for your success on the national exam.
I don’t think many Japanese people know Japan’s national sport "sumo" used to be a ritual to pray for a bountiful rice harvest.