Reputed exorcist from the Archdiocese of Barcelona in Catalonia, Spain, Father Juan José Gallego, has said that in his experience pride is the devil's favorite sin.
Citing excerpts from an interview conducted by the Spanish daily El Mundo, Gallego, who is in his ninth year as an appointed exorcist, said pride is the sin the devil likes the most and explained that he had a lot of fear when he first started evicting demons from human vessels.
"In the beginning I had a lot of fear," said Gallego. "All I had to do was look over my shoulder and I saw demons. … The other day I was doing an exorcism, 'I command you! I order you!'… and the Evil One, with a loud voice fires back at me: 'Galleeeego, you're over-doooing it.' That shook me."
He said he stood his ground because he knows God is more powerful than the devil.
When he first got appointed as an exorcist, Gallego said relatives expressed concern for his safety.
"When they appointed me, a relative told me, 'Whoa, Juan José, I'm really afraid, because in the movie 'The Exorcist,' one person died and the other threw himself through a window.' I said to her, 'Don't forget that the devil is [just a] creature of God,'" he explained.
Gallego added that when people are possessed "they lose consciousness, they speak strange languages, they have inordinate strength, they feel really bad, you see very well-mannered people vomiting and blaspheming."
Recalling one case in particular, Gallego said: "There was a boy whom the demon would set his shirt on fire at night and things like that. He told me what the demons were proposing him to do: If you make a pact with us, you'll never have to go through any more of what you're going through now."
He also explained that addictions are "a type of possession" because "when people are going through a crisis they suffer more. They can feel hopeless, People feel like they've got the devil inside."
According to Paul Sands, associate professor of Theology at the Georger W. Truett Theological Seminary at Baylor University, "Christians have long counted pride as a sin — indeed the 'original sin' that generates every other and is the vital principle of each."
And Isaiah 14:12–15 first highlights pride's beginning in the Bible in the devil.
"How are you fallen from Heaven, O Lucifer, son of the morning! How are you cut down to the ground, which did weaken the nations! For you have said in your heart, I will ascend into Heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north: I will ascend above the heights of the clouds; I will be like the most High. Yet you shall be brought down to Hell, to the sides of the pit," reads the Scripture.