Article 1. Those whom God has accepted in the beloved, effectually called, sanctified by His Spirit, and given the precious faith of His elect can neither totally nor finally fall from the state of grace, but shall certainly persevere therein to the end and be eternally saved.
Article 2. This perseverance of the saints does not depend on their own free will, but on the immutability of the decree of election, flowing from the free and unchangeable love of God the Father, and on the efficacy of the merit and intercession of Jesus Christ, the saints' union with Him, the oath of God, the abiding of His Spirit, and the nature of the new covenant. From all these arises also the certainty and infallibility of this perseverance.
Article 3. They may, through the temptations of Satan and of the world, the prevalency of corruption remaining in them, and the neglect of 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 have their graces and comforts impaired, have their hearts hardened and their consciences wounded, hurt and scandalize others, and bring temporal judgments upon themselves. Nevertheless, they shall renew their repentance and be preserved through faith in Christ Jesus until the end.
Article 2. This perseverance of the saints does not depend on their own free will, but on the immutability of the decree of election, flowing from the free and unchangeable love of God the Father, and on the efficacy of the merit and intercession of Jesus Christ, the saints' union with Him, the oath of God, the abiding of His Spirit, and the nature of the new covenant. From all these arises also the certainty and infallibility of this perseverance.
Article 3. They may, through the temptations of Satan and of the world, the prevalency of corruption remaining in them, and the neglect of 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 have their graces and comforts impaired, have their hearts hardened and their consciences wounded, hurt and scandalize others, and bring temporal judgments upon themselves. Nevertheless, they shall renew their repentance and be preserved through faith in Christ Jesus until the end.
Q. Can they be saved who are unthankful, and remain still careless in their sins, and are not converted from their wickedness to God?
A. By no means; for as the Scripture bears witness, neither unchaste persons, nor idolaters, nor adulterers, nor thieves, nor covetous, nor drunkards, nor slanderers, nor robbers, shall enter into the kingdom of God.
An Orthodox Catechism, Question 92.