True ministers of the gospel can neither give faith or joy nor sustain it; faith is the gift of God (Eph. 2:8-9). True ministers of the gospel do not seek dominion over a believer's faith.
However, in preaching the gospel of Christ, when blessed by the power of the Holy Spirit, believers do grow in faith and in the knowledge of Christ through the preaching of the truth (1 Peter 2:2; 2 Peter 3:18).
We are but helpers, or means and instruments, which God has ordained to preach the gospel and to instruct believers in the Word that they might grow in faith (Rom. 10:17) and to cause His people to rejoice in Christ Jesus; faith and joy go and grow together (Rom. 5:1-2). As we grow in faith we also grow in joy (Phil.3:3). My prayer is this, Lord enable me to be a faithful helper of your faith and joy in Christ, not a hindrance.