Deuteronomy 30:6 - Circumcision of the Heart.

Deu 30:6 (KJV)  And the LORD thy God will circumcise thine
heart, and the heart of thy seed, to love the LORD thy God with all
thine heart, and with all thy soul, that thou mayest live.

Deu 30:6 (TEV)  The LORD your God will give you and your
descendants obedient hearts, so that you will love him with all your heart,
and you will continue to live in that land.

Deu 30:6 (CEV)  You and your descendants are stubborn, but the
Lord will make you willing to obey him and love him with all your
heart and soul, and you will enjoy a long life.

God's mercy is unbelievable. It goes far beyond what we can
imagine. Even if the Jews deliberately walked away from him and ruined
their lives, God would still take them back. God would give them
inward spiritual renewal (circumcise their hearts). God wants to
forgive us and bring us back to himself too. Some people will not learn
this until their world has crashed in around them. Then the sorrow
and pain seem to open their eyes to what God has been saying all
along. Are you separated from God by sin? No matter how far you have
wandered, God promises a fresh beginning if only you will turn to him.
[Life Application SB]

Do you remember when you said "yes" to Jesus? How long ago was
it? A few months maybe years? I said "yes" to the Lord in November
1964 when I was a teenager. But I also said "yes" to Him just the
other day. (Diamonds in Dust by Joni Eareckson Tada) [Inspirational
SB]

It is God that circumcises the heart. The whole work is the
Lord's from the beginning to the end. 1SM391,2

Phil 2:13 (KJV)  For it is God which worketh in you both to will
and to do of his good pleasure.

For the Lord himself here engages to "circumcise their hearts;"
and when regenerating grace has removed corrupt nature, and Divine
love has supplanted the love of sin, they certainly will reflect,
repent, return to God, and obey him; and he will rejoice in doing them
good. The change that will be wrought upon them will not be only
outward, or consisting in mere opinions; it will reach to their souls. It
will produce in them an utter hatred of all sin, and a fervent love
to God, as their reconciled God in Christ Jesus; they will love him
with all their hearts, and with all their soul. [Matthew Henry
Commentary]

He would give them his grace to change their hearts, and rule
there (v. 6): The Lord thy God will circumcise thy heart, to love the
Lord. Note, the heart must be circumcised to love God. The filth of
the flesh must be put away; and the foolishness of the heart, ...Turn
you at my reproof: behold, I will pour out my Spirit, <Prov. 1:23>.
(Matthew Henry's Commentary)

Rom 2:29 (NCV)  A person is a Jew only if he is a Jew inside;
true circumcision is done in the heart by the Spirit, not by the
written law. Such a person gets praise from God rather than from
people.

Rom 8:13 (NCV)  If you use your lives to do the wrong things
your sinful selves want, you will die spiritually. But if you use the
Spirit's help to stop doing the wrong things you do with your body, you
will have true life.

Mat 26:41 (KJV)  Watch and pray, that ye enter not into
temptation: the spirit indeed is willing, but the flesh is weak.

1 Th 5:17 (KJV)  Pray without ceasing.

By the combined influences of the Word and the Spirit of God,
their hearts will be touched and purified. [Jamieson, Fausset, And
Brown Commentary]

Christ answered all the temptations of Satan with "It is
written;" to set us an example, he appealed to what was written in the
Scriptures. [Matthew Henry Commentary]