"Unbelievers stumbling; Believers rejoicing"

There are some who stumble at Christ because of his holiness.

He is too strict for them; they would like to be Christians,
but they cannot renounce their sensual pleasures; they
would like to be washed in his blood, but they desire still
to roll in the mire of sin.

Willing enough the mass of men would be to receive Christ,
if, after receiving him, they might continue in their drunkenness,
their wantonness, and self-indulgence. But Christ lays the axe
at the root of the tree; he tells them that these things must be
given up, for “because of these things the wrath of God comes
upon the children of disobedience,” and “without holiness no
man can see the Lord.”

Human nature kicks at this.

“What! May I not enjoy one darling lust? May I not indulge
myself at least now and then in these things? Must I altogether
forsake my old habits and my old ways? Must I be made a
new creature in Christ Jesus?”

These are terms too hard, conditions too severe, and so the
human heart goes back to the flesh pots of Egypt, and clings
to the garlic and the onions of the old estate of bondage, and
will not be set free even though a greater than Moses lifts up
the rod to part the sea, and promises to give to them a Canaan
flowing with milk and honey.

Christ offends men because his gospel is intolerant of sin.
source