“And I am certain that God, who began the good work within you, will continue his work until it is finally finished on the day when Christ Jesus returns.”Philippians 1:6 NLT
When you were in school you would have to take regular tests. These tests let the teacher know where you stood on the material you needed to learn. If you were unable to pass these tests, then more assignments and more tests would have to be given.
God also gives tests. His tests show where we are on the road of our personal development. In his mercy, God does not take us where we are not ready to go. He prepares us first to ensure we can handle it spiritually, emotionally, physically and the like.