-- if you seek God, you shall find him, if you seek him with all your heart and soul --- Deuteronomy 4:29
-- know God and serve him with a perfect heart and willing mind --- 1 Chronicles 28:9
-- for God searches all hearts, and understands all thoughts --- 1 Chronicles 28:9
-- if you seek him, he will be found of you --- 1 Chronicles 28:9
-- but if you forsake him, he will cast you off for ever --- 1 Chronicles 28:9
-- you shall seek God, and find him, when you search for him with all your heart --- Jeremiah 29:13
-- seek the Lord, feel after him, and find him, though he is not far from any one of us --- Acts 17:27

Deuteronomy 4:29 KJV
[29] But if from thence thou shalt seek the Lord thy God, thou shalt find him, if thou seek him with all thy heart and with all thy soul.

1 Chronicles 28:9 KJV
[9] And thou, Solomon my son, know thou the God of thy father, and serve him with a perfect heart and with a willing mind: for the LORD searcheth all hearts, and understandeth all the imaginations of the thoughts: if thou seek him, he will be found of thee; but if thou forsake him, he will cast thee off for ever.

Jeremiah 29:13 KJV
[13] And ye shall seek me, and find me, when ye shall search for me with all your heart.

Acts 17:27 KJV
[27] That they should seek the Lord, if haply they might feel after him, and find him, though he be not far from every one of us:

A promise from God:

if you seek him
you will find him
if you search for him with all your heart