Psalms 24:10 NIV

Who is he, this King of glory?
The Lord Almighty—
he is the King of glory.

Psalm 24 is one of David psalms that I could not guess where or when he wrote it.  It is a beautiful declaration which is probably why Handel incorporated it into his Messiah.  To me it sounds like Revelations 5:4 which attributes to Him strength and victory in battle.  Just make sure you have let Him in to your heart.