Dear young man,
Do you understand what it means to grow higher and forward?
Let me explain using a ladder and a conventional stairway as examples (ladders are special types of stairways too).
Ladders are structures built straight to climb higher in such a way that each rung is placed directly above, but not forward, the last one.
Which means, going higher requires you step on each rung above the other in a vertical upward manner (like elevators).