Let not your heart be troubled: ye believe in God, believe also in me. John 14:1"
The disciples of Jesus Christ knew of the existence of God before they met Jesus Christ. Apparently, they were expecting the Savior to come even though some doubted the manner in which He came. Jesus Christ knowing, the background of His disciples, had to encourage them to believe in Him as much as they believed in God.
As a Christian leader, you need to make your disciples/followers believe in you as much as they believe in God because Our Father and Our Lord Jesus Christ use people, especially His children, to accomplish His purposes/will on earth. If your disciples do not believe in you or trust you, you are likely to lose them to another leader who may not even be called of God to lead His children.
The heart begins to be troubled when it has no faith/belief in God's leaders. That is why, as a God-chosen leader, you need to follow Christ Jesus as the children of God follow you: in righteousness, truth, loyalty, kindness, working of miracles, meekness, etc. so that your followers can have confidence in you.
Dearly beloved, are you a leader? Do your followers/disciples believe in you?