1 Corinthians 5:1

It is commonly reported that there is lewdness among you, and such lewdness as is not named even amongst the heathens, that one should have his father's wife.

James 1:6-8

But let him ask in faith, nothing doubting; for he that doubteth is like a wave of the sea blown about and tossed by the wind.

2 Peter 2:14

having eyes full of adultery, and which cannot be restrained from sin: ensnaring unstable souls, and having a heart practised in rapine; cursed people:

2 Peter 3:16

as also in all his epistles, speaking in them of these things: in which are some things hard to be understood, which the illiterate and unstable wrest, as they do also the other scriptures, to their own destruction.

Treasury of Scripture Knowledge

Summary

Unstable as water, thou shalt not excel; because thou wentest up to thy father's bed; then defiledst thou it: he went up to my couch.

Bible References

Unstable

James 1:6
But let him ask in faith, nothing doubting; for he that doubteth is like a wave of the sea blown about and tossed by the wind.
2 Peter 2:14
having eyes full of adultery, and which cannot be restrained from sin: ensnaring unstable souls, and having a heart practised in rapine; cursed people:
2 Peter 3:16
as also in all his epistles, speaking in them of these things: in which are some things hard to be understood, which the illiterate and unstable wrest, as they do also the other scriptures, to their own destruction.

Because

1 Corinthians 5:1
It is commonly reported that there is lewdness among you, and such lewdness as is not named even amongst the heathens, that one should have his father's wife.