For Christians who have followed Jesus Christ very long, there should be a trail of God’s faithfulness; there are stories of victory and answered prayers.
The problem is that we are so easy to forget when we face a new challenge. We might even respond with a statement of "this time is different."
We find some examples in scripture where this very thing happened. For instance, the Lord worked several miracles on behalf of the children of Israel when he delivered them from their bondage of slavery in Egypt, including the parting of the Red Sea. Later on when they faced a shortage of water, instead of trusting God for his provision, they doubted, complained and accepted defeat.
In the New Testament, Jesus’ disciples had experienced the miracles of the feeding of the 5,000 and then the 4,000 from just a few fish and a few loaves of bread, but then not long afterward doubted the Lord’s ability to provide bread for just the few disciples.
In Matthew 16 He said to them, "You of little faith, don’t you remember the five loaves for the 5,000, and how many basketfuls you gathered, or the seven loaves for the 4,000 and how many basketfuls you gathered?"
He could easily be saying to us, "Don’t you remember the miracles I performed in your life in the past? Why are you having so little faith?"
When you are facing new challenges in your life – things where you need a miracle from God – take a little time on reflecting what he has already done for you in the past and trust in his faithfulness for your future.