Psalm 27:13-14
13 I believe that I shall look upon the goodness of the Lord
in the land of the living!
14  Wait for the Lord;
 be strong, and let your heart take courage;
wait for the Lord! 
Looking back on the things you have been through in your life can be a double-edged sword at times.  One moment you look back on an event that brought you great joy, and find that to give you great strength for a time.  While other times you allow the negativity of another moment to spiral you down into a deep dark place…
While expressing this confession to the Lord, David can recount how he has been in bad situations and realized the Lord in His goodness has brought him through it.  So because he can look back on his past victories in God, he can bring that into the present, that he will see the goodness of the Lord again!
But what stops us from seeing the goodness of the Lord? Or believing to see it in bad situations?  Generally it is because we have allowed His goodness to be shrouded by our own negativity.  Fear anticipates things going bad or getting worse, while faith like David displays, anticipates the goodness of the Lord to shine through, eventually!
What gives us hope beyond the distress of our past or the present day, is to know the character of the Lord through Jesus Christ, by His Word and Spirit.  God has a way of putting our hearts and minds at rest.  Not because the situation has gone away, or our past can change, but because we trust in His goodness.  Recall His goodness from past situations, and realize His faithful character never changes! (Hebrews 13:8)
LD