Continuity mistake: As the priest descends down the rope ladder into the church for the first time he is handed a lantern by his friend. In the next shot the camera is looking down and you can see that the friend is holding the lantern. Then the next person goes down the same rope ladder and the friend is not holding the lantern, where did the lantern go?
Continuity mistake: In the original film, several priests discuss who should do the exorcism. Merrin was chosen because he had experience (supposedly this film), and that the exorcism lasted a month and it nearly killed him. In this film, the exorcism appeared to have lasted only a few hours and, although I'm sure he was in very real danger, he didn't seem the worse for wear after it was over.
Continuity mistake: As Merrin and Sarah are sitting on the bed about to kiss, the opening of the mosquito net around Joseph's bed changes several times.
Continuity mistake: During Merrin's first conversation with Jeffries, in the Kenyan bar, the liquor bottle on the table rotates several times.
Continuity mistake: In the opening scene, when the priest first sees the demon idol laying on the ground it is a few inches below the soldier's hand. When he reaches down to take it, the idol is grasped in the hand.
Answer: I do. It's just the Latin form of the Ritual Absolution in the Initial Rites from the Mass, applied to the second singular person (it is said with "us", instead of "you"), though it should not be used there with Sarah. In those situations, the proper absolution is the one that belongs to the Sacrament of Reconciliation or, instead, a simple blessing. The translation is: May Almighty God have mercy on you, forgive your sins and lead you to eternal life.