1 Corinthians 5:1

Fornication is truly heard of among you, and such fornication which is not among the heathens, that one should have the wife of his father.

James 1:6-8

But let him ask in faith, doubting as to nothing; for he that doubts is like unto a wave of the sea driven by the winds and tossed by the tempest.

2 Peter 2:14

having eyes full of an adulteress, and unable to cease from sin; beguiling unestablished souls: having a heart which has been made fat with covetousness; children of the curse:

2 Peter 3:16

as also in all his epistles, speaking in the same concerning these things; in which there are some things hard to understand, which the unlearned and unestablished wrest, as they also do 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, doubting as to nothing; for he that doubts is like unto a wave of the sea driven by the winds and tossed by the tempest.
2 Peter 2:14
having eyes full of an adulteress, and unable to cease from sin; beguiling unestablished souls: having a heart which has been made fat with covetousness; children of the curse:
2 Peter 3:16
as also in all his epistles, speaking in the same concerning these things; in which there are some things hard to understand, which the unlearned and unestablished wrest, as they also do the other scriptures, to their own destruction.

Because

1 Corinthians 5:1
Fornication is truly heard of among you, and such fornication which is not among the heathens, that one should have the wife of his father.