Nothing is impossible for God. Therefore he is absolutely trustworthy. You don't get justified by believing that Jesus died for sinners and rose again. You get justified by banking your hope on the promises that God secured and guaranteed for you through the death and resurrection of his Son. The faith by which God justifies us, forgives all our sins, reckons us righteous, is the experience of being satisfied that God will come through for you according to all his promises.
Faith is a power.
It never leaves the life unchanged. It can't, because what you bank your hope on always governs your life. If you bank your hope on money, if your bank your hope on prestige, if you bank your hope on leisure and comfort, if you bank your hope on power or success, it governs the choices you make and the attitudes you develop. And so does banking your hope on the promises of God day by day. Belief in the promises of God is the taproot of all righteousness and love.