His resurrection is God's seal and guarantee that Christ's death settled the sin question and accomplished our justification. Justification is mediately by faith. Faith is not the cause of justification, nor can it be regarded as its ground or basis. It is only a mediating function through which justification is received. It is a prerequisite, but not the cause of justification.
Justification is evidenced by works.
Here there is a contrast between a say so or dead faith and true saving faith. Freedom from condemnation. Peace with God. Assurance and realization of future glorification.