I hold fast
Job 2:3
And the LORD said unto Satan, Hast thou considered my servant Job, that there is none like him in the earth, a perfect and an upright man, one that feareth God, and escheweth evil? and still he holdeth fast his integrity, although thou movedst me against him, to destroy him without cause.
Psalm 18:20-23
20
The LORD rewarded me according to my righteousness; according to the cleanness of my hands hath he recompensed me.
21
For I have kept the ways of the LORD, and have not wickedly departed from my God.
22
For all his judgments were before me, and I did not put away his statutes from me.
23
I was also upright before him, and I kept myself from mine iniquity.
Proverbs 4:13
Take fast hold of instruction; let her not go: keep her; for she is thy life.
my heart
Acts 24:16
And herein do I exercise myself, to have always a conscience void of offence toward God, and toward men.
2 Corinthians 12:11
I am become a fool in glorying; ye have compelled me: for I ought to have been commended of you: for in nothing am I behind the very chiefest apostles, though I be nothing.
1 John 3:20
For if our heart condemn us, God is greater than our heart, and knoweth all things.
1 John 3:21
Beloved, if our heart condemn us not, then have we confidence toward God.