1 John 2:19

These antichrists left our group [i.e., withdrew their fellowship from us], but they were not [really a part] of us, for if they had been, they would have continued [to participate] with us. But, by their leaving us, it proved that none of them were [really] a part of our group [after all].

Acts 20:30

[Indeed, even] from among your own selves [i.e., the body of elders there in Ephesus] some men will arise and, by speaking false things, they will lead away the disciples, [influencing them] to follow them.

1 Corinthians 11:19

For it is to be expected [i.e., it is inevitable] that there would be dissensions among you, so that those who are approved [by God] can become known among you.

Matthew 13:20-21

And the person who was sown on rocky ground is the one who hears the message and immediately welcomes it joyfully,

Matthew 24:24

For false Christs and false prophets will appear and they will perform great [miraculous] signs and [supernatural] wonders in order to lead astray even the elect [i.e., God's people], if possible.

Mark 4:5-6

And some seed fell on rocky ground where there was not much soil, and immediately it sprouted up because the soil was so shallow.

Mark 4:16-17

And in the same way, some [of the seed] that was sown on rocky soil represented those who heard 'the word' and immediately accepted it gladly,

Mark 13:22

For false Christs and false prophets will appear and they will perform [miraculous] signs and [supernatural] wonders in order to lead astray [even] the elect, if possible.

Luke 8:13

And those people [represented by the seed falling] on rocky ground are those who, upon hearing the word [of God], accept it gladly, but since they have no root [system], they believe it for [only] awhile, and [then] in times of trial fall away [from God].

John 4:14

but whoever drinks the water I give him will never get thirsty [again]. For the water I will give him will become in him [i.e., in his spirit] a spring of water, bubbling up and producing never ending life." [See John 7:38].

John 6:37-39

Every person [Note: The Greek says, "every thing"] whom the Father gives me will [eventually] come to me [i.e., for salvation]; and I will never turn away that person who comes to me.

John 10:28-30

I give them never ending life and they will never be destroyed, and no one will [be able to] steal them out of my hand.

John 15:2

He will cut off [See verse 6] every branch [i.e., follower of Christ] who is in [fellowship with] me that does not bear fruit. And He will prune every branch that does bear fruit, so it will bear more fruit.

Acts 15:24

We have heard that certain [men] who left here have been upsetting you people and [even] undermining [some people's] spiritual lives by what they have been teaching. This was done without our authorization [or approval].

Romans 9:6

But it is not as if the word of God [i.e., His promise to Israel] has failed [in its fulfillment]. For not all those descended from the Israelites are [truly] Israelites [i.e., God's people].

Romans 11:5-6

So, now also, there is a small minority which has been selected by God's unearned favor [i.e., to be saved].

2 Timothy 2:10

So, I endure everything for the elect's sake [i.e., God's people], so that they can obtain the salvation which comes through Christ Jesus, with [its] never ending splendor.

2 Timothy 2:19

However, the solid foundation of God stands firm. [Note: This probably refers to the church. See I Tim. 3:15]. It is sealed with these words [i.e., certifying God's ownership and a commitment to Him]: "The Lord knows those who are His people," [See Num. 16:5], and "Everyone who confesses the name of the Lord should stop practicing wickedness." [See Isa. 36:13].

2 Timothy 3:9

But they will not advance any farther [in their sin] because their foolish ways will become obvious to everyone, just as those of Jannes and Jambres were.

Hebrews 10:39

But we are not like those people who turn back and are destroyed, but like those who have faith [in God] and obtain the salvation of their souls.

1 Peter 1:2-5

These people have been [specially] selected, and [their acceptance was] pre-planned by God the Father, and they were set apart through [the work of] the Holy Spirit. This resulted in their obedience and sprinkling [Note: This is a figurative reference to the Old Testament practice of cleansing, See Exodus 24:7-8] by the blood of Jesus Christ. May God's unearned favor and peace be continually upon you.

2 Peter 2:20-21

For if people who have escaped from the defiling practices of the world by coming to know our Lord and Savior Jesus Christ, become tangled up in them again, and are overcome by them, these people are worse off than before they were converted.

Jude 1:1

[This is being written by] Jude, a slave of Jesus Christ, and a brother of James [Note: This "Jude" was probably not the apostle. See verses 17-18], to those who have been called [by God], who are also loved in [fellowship with] God the Father, and who are kept [safe] in [fellowship with] Jesus Christ.

Jude 1:19

These are people who cause divisions [among God's people]; they follow their natural inclinations [i.e., worldly principles], for they do not have the Holy Spirit [in their lives].

Treasury of Scripture Knowledge

Summary

They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.

Bible References

Went out

Matthew 13:20
And the person who was sown on rocky ground is the one who hears the message and immediately welcomes it joyfully,
Mark 4:5
And some seed fell on rocky ground where there was not much soil, and immediately it sprouted up because the soil was so shallow.
Luke 8:13
And those people [represented by the seed falling] on rocky ground are those who, upon hearing the word [of God], accept it gladly, but since they have no root [system], they believe it for [only] awhile, and [then] in times of trial fall away [from God].
John 15:2
He will cut off [See verse 6] every branch [i.e., follower of Christ] who is in [fellowship with] me that does not bear fruit. And He will prune every branch that does bear fruit, so it will bear more fruit.
Acts 15:24
We have heard that certain [men] who left here have been upsetting you people and [even] undermining [some people's] spiritual lives by what they have been teaching. This was done without our authorization [or approval].
Acts 20:30
[Indeed, even] from among your own selves [i.e., the body of elders there in Ephesus] some men will arise and, by speaking false things, they will lead away the disciples, [influencing them] to follow them.
2 Peter 2:20
For if people who have escaped from the defiling practices of the world by coming to know our Lord and Savior Jesus Christ, become tangled up in them again, and are overcome by them, these people are worse off than before they were converted.
Jude 1:19
These are people who cause divisions [among God's people]; they follow their natural inclinations [i.e., worldly principles], for they do not have the Holy Spirit [in their lives].

They might

Romans 9:6
But it is not as if the word of God [i.e., His promise to Israel] has failed [in its fulfillment]. For not all those descended from the Israelites are [truly] Israelites [i.e., God's people].
Romans 11:5
So, now also, there is a small minority which has been selected by God's unearned favor [i.e., to be saved].
1 Corinthians 11:19
For it is to be expected [i.e., it is inevitable] that there would be dissensions among you, so that those who are approved [by God] can become known among you.
2 Timothy 3:9
But they will not advance any farther [in their sin] because their foolish ways will become obvious to everyone, just as those of Jannes and Jambres were.
Hebrews 10:39
But we are not like those people who turn back and are destroyed, but like those who have faith [in God] and obtain the salvation of their souls.

General references

Matthew 25:2
Five of the bridesmaids were foolish and five were sensible.
John 10:5
They will not follow a stranger, but will run from him, for they do not recognize the voice of strangers."
1 Timothy 5:15
For some [young widows] have already turned away [from their commitment to God] to serve Satan.