Based on John 15: 1-5, "I Am the Holy Vine" versifies Jesus' teaching about leading fruitful lives. Using the common Old Testament symbol of a vineyard (Ps. 80; Isa. 5; Jer. 2:21), Jesus points out that love can be produced only by being rooted in the source of true love, Christ, in the Father's vineyard. Whereas the
Old Testament vineyard is sometimes pictured as unfruitful, Jesus casts himself as "the true vine" that produces good fruit.
Bert Polman, Psalter Hymnal Handbook
In baptism, our identity is established and we are “set apart from all other people and alien religions, that we may wholly belong to [Christ] whose mark and sign we bear” (Belgic Confession, Article 34). Heidelberg Catechism, Lord’s Day 26, Question and Answer 70 assures us that “to be washed with Christ’s Spirit means that the Holy Spirit has renewed and sanctified us to be members of Christ…” We therefore are called “to join and unite with it [the church of Christ]” (Belgic Confession, Article 28). This union with Christ shapes our personal identity for all time.