2 Peter 2:20-22

Now, if, having fled away from the pollutions of the world, through the knowledge of the Lord and Saviour Jesus Christ, and being again entangled, they are overcome by them; their last condition is worse than the first.

1 John 2:19

They went away from us, but they were not of us. For, if they had been of us, they would have abode with us; but they went away, that they might be made manifest that they were not of us.

Treasury of Scripture Knowledge

Summary

From that time many of his disciples went back, and walked no more with him.

Bible References

Of his

2 Peter 2:20
Now, if, having fled away from the pollutions of the world, through the knowledge of the Lord and Saviour Jesus Christ, and being again entangled, they are overcome by them; their last condition is worse than the first.
1 John 2:19
They went away from us, but they were not of us. For, if they had been of us, they would have abode with us; but they went away, that they might be made manifest that they were not of us.