On perseverance in the line that has been chosen.
Wherefore it is good and profitable for each one to endeavour with all his might and main to attain perfection in the work that has been begun, according to the line which he has chosen as the grace which he has received; and while he praises and admires the virtues of others, not to swerve from his own line which he has once for all chosen, as he knows that, as the Apostle says, the body of the Church indeed is one, but the members many, and that it has “gifts differing according to the grace which is given us, whether prophecy, according to the proportion of the faith, whether ministry, in ministering, or he that teacheth, in doctrine, or he that exhorteth in exhortation, he that giveth, in simplicity, he that ruleth, with carefulness, he that showeth mercy, with cheerfulness.” 1870 For no members can claim the offices of other members, because the eyes cannot perform the duties of the hands, nor the nostrils of the ears. And so not all are Apostles, not all prophets, not all doctors, not all have the gifts of healing, not all speak with tongues, not all interpret. 1871
Cf. 1 Cor. xii. 28.