1 Corinthians 5:1

It is actually reported that there is fornication among you, and of a kind unheard of even among the Gentiles--a man has his father's wife!

James 1:6-8

But let him ask in faith and have no doubts; for he who has doubts is like the surge of the sea, driven by the wind and tossed into spray.

2 Peter 2:14

Their very eyes are full of adultery--being eyes which never cease from sin. These men set traps to catch unstedfast souls, their own hearts being well trained in greed. They are fore-doomed to God's curse!

2 Peter 3:16

That is what he says in all his letters, when speaking in them of these things. In those letters there are some statements hard to understand, which ill-taught and unprincipled people pervert, just as they do the rest of the Scriptures, to their own ruin.

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 and have no doubts; for he who has doubts is like the surge of the sea, driven by the wind and tossed into spray.
2 Peter 2:14
Their very eyes are full of adultery--being eyes which never cease from sin. These men set traps to catch unstedfast souls, their own hearts being well trained in greed. They are fore-doomed to God's curse!
2 Peter 3:16
That is what he says in all his letters, when speaking in them of these things. In those letters there are some statements hard to understand, which ill-taught and unprincipled people pervert, just as they do the rest of the Scriptures, to their own ruin.

Because

1 Corinthians 5:1
It is actually reported that there is fornication among you, and of a kind unheard of even among the Gentiles--a man has his father's wife!