Halifax nuts

(Thomas Brooks, "The Crown and Glory of Christianity,
 or, HOLINESS, the Only Way to Happiness", 1662)

A man may be visibly holy—who is not inwardly holy.
A man may have an outward dress of holiness upon him
—who has not the spirit and vitality of holiness in him.

They say of Halifax nuts, that they are all shells—with
no kernels. Just so, there are many who make a glorious
show before men—who are abominable in the sight of
God; who are gold in man's eyes—but dirt in God's sight.

"In the same way, on the outside you appear to people
 as righteous; but on the inside you are full of hypocrisy
 and wickedness." Matthew 23:28

They were outwardly religious—but inwardly wicked; they
had the semblance of sanctity—but inwardly very full of
impurity; they were fair professors—but foul sinners; they
were gracious without—but impious within. Look! as those
are the worst of vices which are covered over with the show
of virtue; so they are the worst of sinners, who cover over
their inward filthiness with the disguises of outward holiness.

The Egyptian temples were fair on the outside—but foul and
filthy within. Such were the Scribes and Pharisees in Christ's
days—and such are many professors in our days!

God will at last hate that man to hell, yes, cast him into the
hottest place in hell—who has a form of godliness upon him;
but nothing of the reality and power of holiness in him.

"You snakes! You brood of vipers! How will you escape
 being condemned to hell!" Matthew 23:33