Hello
@Andrew98, the Lord has also promised that He will sanctify us
(grow us up in Christlikeness) and "preserve" those of us who are truly His in the faith .. e.g.
Philippians 1:6, 2:13; 1 Thessalonians 5:23-24, Hebrews 7:25, such that we will persevere in the faith from justification to Glory .. albeit highly imperfectly in some cases. Perseverance is therefore one of principle ways that we know that we are "in Christ" .. e.g.
2 Corinthians 13:5.
Further, if a man
(in his right mind), who claimed and perhaps believed himself to be a Christian at one time, eventually leaves the Christian faith/rejects the Lord, and he dies in unrepentant sin, then the Lord tells us plainly, through the pen of the Apostle John, that he was ~
never~ a Christian from the get-go .. e.g.
1 John 2:19.
Finally, St. James speaks of two 'kinds' of faith, one saving/lively
(which is the kind of faith that results in good works, holy living and perseverance), and another kind of faith that is dead, that ~results~ in nothing. The demons "
believe" in the latter sense
(and they even "shudder" because they do) ..
James 2:19, because they know exactly who Jesus is ..
Mark 5:1-9 (see v7, in particular), but they are not, nor will they ever be, saved.
These are some of the reasons why we Calvinists hold to the doctrine of, "
The Perseverance of the Saints"
(see below), not to "OSAS", because ~many~ have claimed and even believed themselves Christians, when they are not/never were ..
Matthew 7:22-23.
God bless you!
--David
p.s. - here is an excerpt from the Westminster Standards,
Westminster Confession of Faith. This is what Calvinists believe
(in part) concerning the Eternal Security of the believer, that all true saints/all who are 'truly' saved by God, 'will' persevere in the Christian faith because of Him.
Chapter 17: Of the Perseverance of the Saints
1. They whom God hath accepted in his Beloved, effectually called and sanctified by his Spirit, can neither totally nor finally fall away from the state of grace; but shall certainly persevere therein to the end, and be eternally saved.a
a.
John 10:28-29;
Phil 1:6;
1 Pet 1:5,
9;
2 Pet 1:10;
1 John 3:9.
2. This perseverance of the saints depends, not upon their own free will, but upon the immutability of the decree of election, flowing from the free and unchangeable love of God the Father;a upon the efficacy of the merit and intercession of Jesus Christ;b the abiding of the Spirit and of the seed of God within them;c and the nature of the covenant of grace:d from all which ariseth also the certainty and infallibility thereof.e
a.
Jer 31:3;
2 Tim 2:18-19. • b.
Luke 22:32;
John 17:11,
24;
Heb 7:25;
9:12-15;
10:10,
14;
13:20-21;
Rom 8:33-39. • c.
John 14:16-17;
1 John 2:27;
3:9. • d.
Jer 32:40. • e.
John 10:28;
2 Thes 3:3;
1 John 2:19.
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;a and for a time continue therein:b whereby they incur God’s displeasure,c and grieve his Holy Spirit;d come to be deprived of some measure of their graces and comforts;e have their hearts hardened,f and their consciences wounded;g hurt and scandalize others,h and bring temporal judgments upon themselves.i
a.
Mat 26:70,
72,
74. • b. Psa 51 title with v. 14. • c.
2 Sam 11:27;
Isa 64:5,
7,
9. • d.
Eph 4:30. • e.
Psa 51:8,
10,
12;
Song 5:2-4,
6;
Rev 2:4. • f.
Isa 63:17;
Mark 6:52;
16:14. • g.
Psa 32:3-4;
51:8. • h.
2 Sam 12:14. • i.
Psa 89:31-32;
1 Cor 11:32.
.