Those Who Fall Away

Every branch in Me that does not bear fruit He takes away; and every branch that bears fruit He prunes, that it may bear more fruit.
John 15:2 NKJV

And this:

Many will say to Me in that day, ‘Lord, Lord, have we not prophesied in Your name, cast out demons in Your name, and done many wonders in Your name?’  And then I will declare to them, ‘I never knew you; depart from Me, you who practice lawlessness!’
Matthew 7:22-23 NKJV

This is similar to this:

the master of that servant will come on a day when he is not looking for him, and at an hour when he is not aware, and will cut him in two and appoint him his portion with the unbelievers.
Luke 12:46 NKJV

And this one:

the master of that servant will come on a day when he is not looking for him and at an hour that he is not aware of,  and will cut him in two and appoint him his portion with the hypocrites. There shall be weeping and gnashing of teeth.
Matthew 24:50-51 NKJV

And better expounded here:

Moreover, brethren, I do not want you to be unaware that all our fathers were under the cloud, all passed through the sea, all were baptized into Moses in the cloud and in the sea, and all drank the same spiritual drink. For they drank of that spiritual Rock that followed them, and that Rock was Christ. But with most of them God was not well pleased, for their  bodies  were scattered in the wilderness. Now these things became our examples, to the intent that we should not lust after evil things as they also lusted. Now all these things happened to them as examples, and they were written for our admonition, upon whom the ends of the ages have come.
I Corinthians 10:1-2, 4-6, 11 NKJV

These verse MUST be used when interpreting these other verses so that they can be properly reconciled.

For certain men have crept in unnoticed, who long ago were marked out for this condemnation, ungodly men, who turn the grace of our God into lewdness and deny the only Lord God and our Lord Jesus Christ.
Jude 1:4 NKJV

They went out from us, but they were not of us; for if they had been of us, they would have continued with us; but they  went  out  that they might be made manifest, that none of them were of us. BUT YOU have an anointing from the Holy One, and you know all things.
I John 2:19-20 NKJV

This is why we are commanded to search out our salvation with fear and trembling. There are many who think they are somewhere they aren't.

Therefore, my beloved, as you have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling; for it is God who works in you both to will and to do for His good pleasure.
Philippians 2:12-13 NKJV