There has been one in this world called Jesus of Nazareth, and it is he who says to you, “Let not your heart be troubled . . . believe in me,” which means, “Come to me, tell me your troubles, tell me all about your difficulty about God, the difficulty of prayer, the difficulty about your weak will and failure.”
I do not care what it is that makes you restless and ill at ease. It may be the possibility of war, it may be illness, it may be business troubles, it may be your own weakness morally in the realm of the will—whatever it is, whatever is troubling and making you unhappy, go to him about it. He is the one who loved you enough to die for you. He said, “Come unto me, all ye that labour and are heavy laden, and I will give you rest” (Matthew 11:28). There is no need for you to be unhappy and restless. Believe in God. Believe in the Son of God, the Lord Jesus Christ who came on earth to deliver you from that very thing and who has removed every barrier between you and God and who can give you rest and peace here and now.
Martyn Lloyd-Jones, Let Not Your Heart Be Troubled (Kindle Edition)