Jamieson, Fausset and Brown on 1 Chronicles 28:9-10

9-10. And thou, Solomon my son--The royal speaker now turns to Solomon, and in a most impressive manner presses upon him the importance of sincere and practical piety.

know thou--He did not mean head knowledge, for Solomon possessed that already, but that experimental acquaintance with God which is only to be obtained by loving and serving Him.