What does the Bible say about faith and believing in Christ?

In Mark 9, we see a father whose son is possessed by a spirit, highlighting the critical nature of faith. Jesus tells the father that all things are possible to him who believes, emphasizing that while Christ has the power to save, the true issue lies within our ability to believe. This reflects the truths of sovereign grace theology, which asserts that apart from God's grace, we have no power to believe or rely on Christ’s finished work for our salvation. The story encourages believers to seek Christ's help not only in salvation but also in growing their faith.