"Knowledge" of God is the study and fulfillment of His Will revealed in His Commandments and expressed by the Prophets, Jesus Christ, and the Apostles in the Holy Scriptures.
"Knowledge" of Christ is the knowledge of the Prophets' Scriptures about Christ, the knowledge and fulfillment of Christ's Teachings about God's Will, the comprehension of His way of life, the motives for His actions, the purpose, the meaning of His Good News of God's Will.