2 Corinthians 11:3
But I am afraid that as the serpent deceived Eve by his cunning, your thoughts will be led astray from a sincere and pure devotion to Christ.Above all, we want to be fully devoted to God. Pray that we have sincere and pure devotion.
from "30 Ways to Pray for Missionaries," compiled by Elaine Helms for the NAMB. (the full list in pdf form is available here)