For of the things which are within the power of the will, as being good and present, you have a proper and regulated desire: but of the things which … - Epictetus

The soul stands on unassailable ground, if it has abandoned external things; it is independent in its own fortress; and every weapon that is hurled falls short of the mark. Fortune has not the long reach with which we credit her; she can seize none except him that clings to her. Let us then recoil from her as far as we are able. This will be possible for us only through knowledge of self and of the world of Nature. The soul should know whither it is going and whence it came, what is good for it and what is evil, what it seeks and what it avoids, and what is that Reason which distinguishes between the desirable and the undesirable, and thereby tames the madness of our desires and calms the violence of our fears. Some men flatter themselves that they have checked these evils by themselves even without the aid of philosophy; but when some accident catches them off their guard, a tardy confession of error is wrung from them. Their boastful words perish from their lips when the torturer commands them to stretch forth their hands, and when death draws nearer!

Don’t give in to second thoughts, because no one who wavers will make progress

Avoid talking often and excessively about your accomplishments and dangers, for however much you enjoy recounting your dangers, it's not so pleasant for others to hear about your affairs.