Deuteronomy 10:16

and ye have circumcised the foreskin of your heart, and your neck ye do not harden any more;

Jeremiah 4:4

Be circumcised to Jehovah, And turn aside the foreskins of your heart, O man of Judah, and ye inhabitants of Jerusalem, Lest My fury go out as fire, and hath burned, And there is none quenching, Because of the evil of your doings.

Deuteronomy 9:6

and thou hast known, that not for thy righteousness is Jehovah thy God giving to thee this good land to possess it, for a people stiff of neck thou art.

Deuteronomy 30:6

'And Jehovah thy God hath circumcised thy heart, and the heart of thy seed, to love Jehovah thy God with all thy heart, and with all thy soul, for the sake of thy life;

Leviticus 26:41

also I walk to them in opposition, and have brought them into the land of their enemies -- or then their uncircumcised heart is humbled, and then they accept the punishment of their iniquity, --

Romans 2:28-29

For he is not a Jew who is so outwardly, neither is circumcision that which is outward in flesh;

Colossians 2:11

in whom also ye were circumcised with a circumcision not made with hands, in the putting off of the body of the sins of the flesh in the circumcision of the Christ,

Deuteronomy 9:13

And Jehovah speaketh unto me, saying, I have seen this people, and lo, a people stiff of neck it is;

Deuteronomy 31:27

for I -- I have known thy rebellion, and thy stiff neck; lo, in my being yet alive with you to-day, rebellious ye have been with Jehovah, and also surely after my death.

Jeremiah 4:14

Wash from evil thy heart, O Jerusalem, That thou mayest be saved, Till when dost thou lodge in thy heart Thoughts of thy strength?

James 4:6-7

and greater grace he doth give, wherefore he saith, 'God against proud ones doth set Himself up, and to lowly ones He doth give grace?'

Treasury of Scripture Knowledge

Summary

Circumcise therefore the foreskin of your heart, and be no more stiffnecked.

Bible References

Stiff-necked

Deuteronomy 9:6
and thou hast known, that not for thy righteousness is Jehovah thy God giving to thee this good land to possess it, for a people stiff of neck thou art.
Deuteronomy 31:27
for I -- I have known thy rebellion, and thy stiff neck; lo, in my being yet alive with you to-day, rebellious ye have been with Jehovah, and also surely after my death.
James 4:6
and greater grace he doth give, wherefore he saith, 'God against proud ones doth set Himself up, and to lowly ones He doth give grace?'