Bucer’s entire theology of justification is that of double justification. Everywhere he speaks of imputed righteous, he always follows directly with inherent righteousness. I will quote a few examples.
Bucer penned the statement on justification at the Colloquy of Regensburg. I have pieced it together through two secondary sources. He writes:
The movement wrought by the Holy Spirit whereby, truly repenting of their old life, men are turned to God and truly apprehend his mercy promised in Christ, so that now they truly believe that they have received forgiveness of sins and reconciliation through the merit of Christ by the free gift of God’s goodness, and they cry out to God, ‘Abba, Father’: but this happens to no one unless there is also at the same time infused into him that love which heals the will… Therefore living faith is that which apprehends God’s mercy in Christ and believes that the righteousness of Christ is freely imputed to oneself, and at the same time receives the promise of the Holy Spirit and also love… But it remains true that we are justified, that is, accepted and reconciled to God by this faith in so far as it apprehends God’s mercy and the righteousness which is imputed to us on account of Christ and his merit, not on account of the worth or perfection of the righteousness which is imparted to us in Christ.
quoted in David F. Wright “Martin Bucer 1491-1551: Ecumenical Theologian,” in Common Places of Martin Bucer trans. and edited by D. F. Wright, 43
We think that in this begun righteousness is really a true and living righteousness, and a noble excellent gift of God; and that the new life in Christ consists in this righteousness, and that all the saints are also righteous by this righteousness, both before God and before men, ‘and that on account thereof the saints are also justified by a justification of works,’ that is, are approved, commended and rewarded by God.
quoted in Herman Witsius, The Economy of the Covenants Between God and Man Book III. Chap. VIII. 26