Gift and Duty

It is only the fervency of the Spirit that can correct our slothfulness. Hence diligence in doing good requires that zeal which the Spirit of God kindles in our hearts. Why then, someone may say, does Paul exhort us to cultivate this fervency? To this I answer - that though it be the gift of God, it is yet a duty enjoined the faithful to shake off sloth and to cherish the flame kindled by heaven, as it for the most part happens, that the Spirit is suppressed and extinguished through our fault. (John Calvin on Romans 12:11, Commentary on Romans)