Pope Francis offered a checklist for Catholics to keep track of how they measure up to the biblical admonition: "If anyone says, 'I love God,' but hates his brother, he is a liar."

Preaching Jan. 10 about the passage from the First Letter of John, the pope said the devil is defeated by Christians loving their brothers and sisters.

To see how one is doing in the battle, the first question to ask is: "Do I pray for people? For everyone, concretely, those whom I like and those I don't like, for those who are friends and those who are not?" the pope said during morning Mass in the chapel of the Domus Sanctae Marthae.

The second thing to check, he said, is how often "I feel inside me sentiments of jealousy, envy, and I start wanting to wish something bad would happen to him or her -- that is a signal that you do not love. Stop there. Don't let those feelings grow. They are dangerous."

Last, he said, the most common sign "that I don't love my neighbor and so cannot say I love God is gossip. Get this clearly into your heart and your head: If I gossip, I do not love God because gossip destroys people."