Septuagesima: "Run so as to obtain the prize."

"Fratres, Nescitis quod ii qui in stadio currunt, omnes quidem currunt, sed unus accipit bravium? Sic currite, ut comprehendatis." (1 Cor 9, 24-27; 10, 1-5)

"Know you not that they that run in the race, all run indeed, but one receiveth the prize? So run that you may obtain."

Self-mastery is the work of Lent for which we prepare on Septuagesima.
  

^"And every one that striveth for the mastery, refraineth himself from all things: and they indeed that they may receive a corruptible crown; but we an incorruptible one.

^"I therefore so run, not as at an uncertainty: I so fight, not as one beating the air:

^"But I chastise my body, and bring it into subjection: lest perhaps, when I have preached to others, I myself should become a castaway."

"Self-mastery is a long and exacting work. One can never consider it acquired once and for all. It presupposes renewed effort at all stages of life. The effort required can be more intense in certain periods, such as when the personality is being formed during childhood and adolescence." (CCC 2342)

The prize won by running the race through self-mastery which brings holiness of life here on earth is eternal life on high in Christ Jesus our Lord.