the time above all others to trust in God

 And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.  

Matthew 17:20 

Throughout the history of God's people great mountains of difficulty, apparently insurmountable, have loomed up before those who were trying to carry out the purposes of Heaven. Such obstacles are permitted by the Lord as a test of faith. When we are hedged about on every side, this is the time above all others to trust in God and in the power of His spirit. The exercise of a living faith means an increase of spiritual strength and the development of an unfaltering trust. It is thus that the soul becomes a conquering power. Before the demand of faith, the obstacles placed by Satan across the pathway of the Christian will disappear; for the powers of heaven will come to his aid. "Nothing shall be impossible unto you." Matthew 17:20  PK595 

The Lord allows trials to come to us to test our faith. They help us see that our need for Jesus in our lives is greater than we often realize. The trials also help us see our need to put our whole dependence on Him. And they help us build our trust in Him. He allows things into our lives to slowly build our characters to more and more reflect Him.