In these verses is one of the Bible's great statements of the Plan of God for every person. We are part of an eternal, comprehensive program which God is accomplishing by means of Jesus Christ. The Lord wants every individual to accept Christ as Savior. The Lord's desire is that every Christian believer grows in grace and in the knowledge of Christ, by means of the Word of God and the ministry of the Holy Spirit. God the Father intends to use growing Christians to demonstrate His Grace to the whole cosmos, including even angelic forces of darkness.
Angels are the students.
This verse continues the statement of verses 9 and 10. It brings missionary activity into the perspective of the overall plan of God. And is is very encouraging for Christians to realize that the Plan of God is so comprehensive. And God's program is centered in the Lord Jesus Christ. The elect angels rejoice with every convert.