But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, — Galatians 5:22

Joy isn't something you manufacture — it's fruit, grown by the Spirit. The kingdom of God is righteousness, peace, and joy in the Holy Spirit, which means this joy doesn't depend on your circumstances. It intimately: sorrowful yet always rejoicing, poor yet making many rich. Even Jesus, for the joy set before Him, endured the cross. Your joy is rooted in what Christ has already done and secured, not in how you feel today.