"Lest there be any fornicator or profane person, etc.
---As
he had before exhorted them to holiness,
---so now, that he might reclaim
them from defilements opposed to it,
---he mentions a particular kind of
defilement, and says, “Lest there be any fornicator.”
But he immediately
comes to what is general, and adds, “or a 
profane person;” for it is
the term that is strictly contrary to holiness.
The Lord calls us for
this end, that He may make us holy unto obedience: this is done when we
renounce the world; but any one who so delights in his own filth that he
continually rolls in it, profanes himself.
As Esau, etc. This example may be viewed as an exposition of the word profane; for when Esau set more value on one meal than on his birthright, he lost his blessing.
That we indeed set a high value on things which are nearly worth nothing, arises from this, — that depraved lust dazzles our eyes and thus blinds us.
*If therefore we would hold a
place in God’s sanctuary, we must learn to despise morsels of meat of
this kind, by which Satan is wont to catch the reprobate.
When he would have inherited the blessing, etc. He
at first regarded as a sport the act by which he had sold his
birthright, as though it was a child’s play; but at length, when too
late, he found what a loss he had incurred, when the blessing
transferred by his father to Jacob was refused to him.
---Thus they who are
led away by the allurements of this world alienate themselves from God,
and sell their own salvation that they may feed on the morsels of this
world,....When too late
their eyes are opened, so that being warned by the sight of their own
wickedness, they become sensible of the loss of which they made no
account.
While Esau was hungry, he
cared for nothing but how he might have his stomach well filled; .... The word “rejected” means that he was repulsed, or denied his
request.
For he found no place of repentance, etc.;
that is, he profited nothing, he gained nothing by his late repentance,
though he sought with tears the blessing which by his own fault he had
lost." Calvin