Jamie Gerrard of The Pilgrim lists various verses about God testing to see what is in the hearts of people. A couple key verses:

Gen 22:12-And He said, “Do not lay your hand on the lad, or do anything to him; for now **I know** that you fear God, since you have not withheld your son, your only son, from Me.”

Exod 16:4-Then the LORD said to Moses, “Behold, I will rain bread from heaven for you. And the people shall go out and gather a certain quota every day, that I may **test them,** whether they will walk in My law or not.

Deut 13:3-”you shall not listen to the words of that prophet or that dreamer of dreams, for the LORD your God is **testing you** ** to know* whether you love the LORD your God with all your heart and with all your soul.

Addition: Psa 139:23 Search me, O God, and know my heart: try me, and know my thoughts:

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