Why God calls Prophets?

God works through Priesthood and Prophets:

Since from the beginning of time, God has called worthy men to speak and relate the message to us as the scriptures says:Surely the Lord God will do nothing, but he revealeth his secret unto his servant the prophets (Amos 3:7).
Because of His love;knowing that we couldn't make our own way to Heaven. And the Lord God... sent ... his messengers, rising up betimes, and sending; because he had compassion on his people, and on his dwelling place(2 Chro. 36:15).
He Ordains and gives Prophets the Priesthood-the power and authority given to man to act in God 's name for the salvation of his children.To learn the gospel of Jesus Christ by Revelation,in turn teach the gospel to us and prophesy and testify of Jesus Christ as the savior and redeemer

(2 Ne. 2:26).whatsoever I command thee thou shalt speak(Jer. 1:7).

If God is the same yesterday, to-day, and forever(1 Ne. 10:18,Heb. 13: 8 Morm. 9: 9 (9-11)) Why will He vary or change?
Paul said prophets were necessary until we all come to a unity of faith(Ephesians 4:11-13 ).

see more: Eph. 2:20,Luke 1:70-72, Acts 3:21 Jer. 7:25.

Teaching them to observe all things whatsoever I have commanded(Matt. 28: 20).

I know that God loves all of us and He will continue

reveal his will, He has called a prophet in this dispensation, his name is Thomas S. Monson.

There is a way to know of this things by asking God in the name of Christ, having faith in Christ,He will manifest by the power of the holy ghost,and by the power of the holy ghost you will know the Truth of all things.