On the perseverance of the saints, 3. Nevertheless, they may, through the temptations of Satan and of the world, the prevalency of corruption remaining in them, and the neglect of the means of their preservation, fall into grievous sins; and, for a time, continue therein: whereby they incur God's displeasure, and grieve His Holy Spirit, come to be deprived of some measure of their graces and comforts, have their hearts hardened, and their consciences wounded, hurt and scandalize others, and bring temporal judgments upon themselves.
-Westminster Confession of Faith on the Perseverance of the Saints 17.3
8. While the Scriptures require self-examination, a believer must remember that his heart can be deceived, and that he is always subject to the temptation to trust in works rather than in Christ. A person should not lightly assume he is saved.
-The Testimony of the RPCNA on Assurance of Faith 18.8
5. Satan has power in the world which includes predictions of the future, signs and wonders that deceive, and possession of persons. Satan often duplicates that which belongs to God even to the establishment of churches that serve him. Therefore, Christians are to flee the working of Satan in such things as fortune telling, horoscopes, astrology, palmistry, witchcraft, conjurings, seances, drug experiences and Satan worship.
-The Testimony of the RPCNA on Providence 5.5 |