Ben Bag Bag says,

"Engage and engage in it

דכלא בה

for all is in it,

and in it you will see

and become old and ancient in it

and do not move from it

שאין לך מדה טובה הימנה

as you will have no better qualification than it..

פרק ה משנה כג

Ben Hei Hei says,

"According to the trouble is the reward."

סליק מסכת אבות