False Apparitions (Divine Mercy, Bayside, Medjugorje)

2 Thessalonians 2:9-12: "Whose coming is according to the working of Satan, in all power, and signs, and lying wonders, And in all seduction of iniquity to them that perish; because they receive not the love of the truth, that they might be saved. Therefore God shall send them the operation of error, to believe lying. That all may be judged who have not believed the truth, but have consented to iniquity."

Sister Faustina's Divine Mercy Devotion is something to avoid

The False Apparitions at Bayside, NY

The False Apparitions at Medjugorje

A sign at Bayside, but not a sign from Heaven

Matthew 24:24-25: "Then if any man shall say to you: Lo here is Christ, or there, do not believe him. For there shall arise false Christs and false prophets, and shall show great signs and wonders, insomuch as to deceive (if possible) even the elect. Behold I have told it to you, before hand. If therefore they shall say to you: Behold He is in the desert, go ye not out: Behold He is in the closets, believe it not."

Besides those covered above, there are many other modern false apparitions. Any apparition which favors Vatican II or the Vatican II antipopes is proven by that fact to contradict Catholic teaching. It therefore cannot be from God.