I attempt an arduous task; but there is no worth in that which is not a difficult achievement.

It was a difficult and arduous task that he accepted without fanfare.

Either do not attempt at all, or go through with it.

It is easy at any moment to surrender a large fortune; to build one up is a difficult and an arduous task.

The search for knowledge is a long and difficult task.

The spirited horse, which will try to win the race of its own accord, will run even faster if encouraged