How often does a man ruin his disciples by remaining always with them! When men are once trained, it is essential that their leader leave them, for without his absence they cannot develop themselves. Plants always remain small under a big tree.
A diamond cannot be polished without friction, nor a person perfected without trials. Someone is enjoying shade today because someone planted a tree a long time ago.
And after we returned to the savannahs and abandoned the trees, did we long for those great graceful leaps and ecstatic moments of weightlessness in the shafts of sunlight of the forest roof?