1 King 3:9 "Give therefore to Your servant an understanding heart to judge Your people and to discern between good and evil. For who is able to judge this great people of Yours?"

Solomon asked Jehovah to give him wisdom and an understanding heart to judge God's people. Wisdom is a matter in our spirit, and understanding is a matter in our mind. The expression an understanding heart actually refers to an understanding in our mind because the mind is the main part of the heart. Quite often we may have wisdom in our spirit but are lacking the capacity to understand in our mind. Thus, we need God's wisdom in our spirit and God's understanding in our mind.

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