1 Corinthians 5:1

It is generally reported that there is lewdness among you; and such lewdness as is not even mentioned among the Gentiles that a certain one has his father's wife.

James 1:6-8

But let him ask in faith, doubting not: for he that doubts, is like a wave of the sea, driven by the wind, and tossed.

2 Peter 2:14

having eyes that are full of the adulteress, and that can not cease from sin, deceiving unstable souls, having a heart exercised in covetousness, accursed children,

2 Peter 3:16

as also in all his letters, speaking in them of these things, in which are some things hard to be understood, which the unlearned 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, doubting not: for he that doubts, is like a wave of the sea, driven by the wind, and tossed.
2 Peter 2:14
having eyes that are full of the adulteress, and that can not cease from sin, deceiving unstable souls, having a heart exercised in covetousness, accursed children,
2 Peter 3:16
as also in all his letters, speaking in them of these things, in which are some things hard to be understood, which the unlearned and unstable wrest, as they do also the other scriptures, to their own destruction.

Because

1 Corinthians 5:1
It is generally reported that there is lewdness among you; and such lewdness as is not even mentioned among the Gentiles that a certain one has his father's wife.