Does TF's Christ-centered approach to justification mean that he sees no role for personal faith? The answer is that TF does see an important role for our personal response of faith, but one that is subordinate to and included in Jesus' own faith (what Scripture refers to as "the faith of Christ").
In his sermons, TF often called people to personal faith in Jesus. But in doing so, he was careful to place personal faith in the context of Christ's own faith. Though to some this might sound like double-talk, it's not. In his vicarious humanity (serving as our substitute and representative), Jesus had faith in the Father, by the Spirit, on our behalf (and he still does!). This is vital to understand because, it's Jesus' faith in God, not our own, that ultimately justifies humanity.
On this important point TF quotes from Scottish minister James Fraser of Brae who stressed, "the correlation of our faith with the faith of God and the faith of Christ," because "human faith derives from, rests on, and is undergirded by divine faithfulness" (loc 1987). Thus TF views justification as entirely Christ's work on our behalf--a work God imputes to us by grace. By the grace of God we are enabled to participate in (personally experience and share in) the faith of Christ himself--the faith by which we are justified before God. The point is this: "justification is accomplished in Christ by Christ for us" (loc 2012). Said another way: Jesus is responsible for our justification from start to finish. He even justifies our weak and flawed personal faith in him!
Thus, according to TF, it's wrong-headed to think of justification as some sort of a transaction that God accomplishes apart from himself. The truth is that justification, like all aspects of our salvation, is a function of the very being of God, in the person of his incarnate Son, Jesus Christ. Said another way, quite simply, yet profoundly: Jesus is our justification! It is in Christ, by him and through him, that we are justified.
So where then does our personal faith come in, if at all? The answer is that we personally (some say "subjectively") experience that justification--we enjoy it personally--as we, by the Spirit sent from Jesus, put our trust in the One who, by his own faith, has justified us. "Justification happens in Christ and consequently in us" (loc 2028).
Eugenio concludes the section of his book that addresses TF's perspective on the "how" of salvation in the person and work of Christ with this important observation:
Torrance's understanding of salvation in Jesus Christ is grounded in the reality of the incarnation of the Son, who, as fully human, is also homoousios [of one being] with the Father. As the Son, his descent [via the incarnation] to created space and time is a salvific movement accomplished by the Triune God in drawing himself near to us in revelation and reconciliation. Likewise, his ascent [via the resurrection] as fully human to the throne of God in his ascension is a salvific movement accomplished from the side of humanity and on behalf of humanity. God's initiative in electing us to salvation is characterized by a double movement: God in Christ's humanward movement and human in Christ's Godward movement. Jesus Christ vicariously redeemed us not only from the side of humanity, but from the side of God (loc 2035).