Therefore let us honor and esteem the merits of the martyrs as being the gifts of God. Let us beg for them, and add the inclination of our own will.
Most often, traditional Roman Catholics defend, and Orthodox and Protestants polemicists decry, the term "merits" within the medieval matrix of "supererogatory works" and "treasury of the saints." St Peter Chrysologus, however, is certainly not medieval, and does not, to my mind, evidence "pre-medieval" tendencies (whatever these may be). Hence, his use of the term "merits" suggests that, perhaps, there is a proper use of the term that neither reactively requires its deletion nor unthinkingly compels it to be understood in a scholastic context.
This suggestion is strengthened by hearing St Peter's use within the larger context:
My brethren, let no one arrogate to his own ability that which no one save God gives. When the Apostle was addressing the martyrs, rightly did he say what you heard when his Epistle was read today: 'You have been given the favor on Christ's behalf--not only to believe in him but also to suffer for him.' Therefore let us honor and esteem the merits of the martyrs as being the gifts of God. Let us beg for them, and add the inclination of our own will. For, our will follows; it does not take the lead. Nevertheless, charity is not lacking if our will is not lacking, for the eager will itself is called charity. Who is there who willingly fears? Who is there who unwillingly loves? May prayer be fervent, and let the feast of this martyr be celebrated. But let everyone who celebrates also imitate him, that the celebrating may not be idle. (Source)
Caveat: I don't have access to the Latin, only Ganss' translation. Perhaps the translation is misleading.