Three things are required for effective prayers

In kindling a fire, three things are needed: a good piece of steel, a good flint, and good tinder. The same is true of prayer. Three things are required—a good teacher, a good believer, and a good teaching—before prayers can be effective and disasters banished from the land. 1/9

The Writings of Nichiren Daishonin
How Those Initially Aspiring to the Way Can Attain Buddhahood through the Lotus Sutra Written to the lay nun Myoho in 1277