Bernard equates God's mercies to us with merit given to us. And that merit he equates with Christ's righteousness. So then the mercy given by God to believers is the merit of Christ, i.e. the righteousness Jesus earned before the law in our place for us.
"My merit, therefore, is the compassion of the Lord; plainly I am not devoid of merit so long as he is not devoid of commiseration. But if the mercies of the Lord are many, equally many are my merits. Shall I sing of my own righteousness? O Lord, I will make mention of thy righteousness alone. That righteousness is mine also, being made mine by God," (Bernard, Serm. 61, in Cantic.) Again, in another passage, "Man's whole merit is to place his whole hope in him who makes the whole man safe," (in Psalm Qui Habitat. Serm. 15.)from Calvin's Institutes