Read Hebrews 11:1
1 Now faith is confidence in what we hope for and assurance about what we do not see. (NIV)
There is a paradox at the heart of our Christian faith. We are both utterly certain and completely uncertain. We both cling tenaciously to truths we regard as central to faith and shrug our shoulders in bewilderment at aspects of that faith we cannot understand.
This text reminds us that our confidence and assurance and our certainty is not the result of some scientific endeavour or rigorous academic exercise. Our faith is not irrational but nor is it simply explicable by intellectual reason. It is both reasonable and beyond reason.
Our confidence in God is not the same as knowing comprehensively what he is doing. I am certain that God is good but not at all certain about the shape of that goodness at any particular time. I am certain God will guide me in the right paths but unsure about what those paths might be. I am certain Jesus will return to claim the earth as his own but I am in the dark as to when and precisely how he will do this. My confidence, ultimately, is in the character of God not in my ability to grasp all there is to know about his character.
Faith is not knowledge, though it contains a degree of knowledge. Faith is not certainty though it is certain about certain things. Therefore faith can coexist with doubt and with uncertainty. Faith is not the result of our psyching ourselves up to feel a particular way or arrogantly believing we know all there is to know about God and life.
Faith remains uncertain about what tomorrow brings but is certain that God will be in that tomorrow.