From Rule of the Congregation of the Missionaries of St. Charles, n. 321

All religious are bound to observe these Rules of Life even though, in themselves, they do not oblige under pain of sin, unless they concern the vows or the laws of God and of the Church.
 

Each member of the Congregation must look on them as the expression of God’s will in his regard, as the special means for his own sanctification and that of the people entrusted to him, and should love and keep them with the greatest exactness and fidelity.

From the observance of these Rules will flow the strength and growth of the Institute; peace and harmony among the missionaries wherever they may be; mutual support and joy even in the midst of difficulties, trials, and persecutions; and, finally, holy perseverance in one’s vocation, and a rich crown of glory in the blessed happiness of life eternal.