The Rosary is a Scriptural prayer in three senses:
1 — The original design of the Rosary was fifteen decades of ten Hail Marys each, 150 in all. This was an imitation of the Liturgy of the Hours (the praying of the Psalms) for those who could not read or chant. 150 Hail Marys for 150 Psalms. The Rosary is “the poor man’s Psalter” or the “Angelic Psalter”. Praying the Rosary is for us a quicker and simpler way to pray the entire Book of Psalms.
2 — Each decade is dedicated to a Mystery of our Lord’s life, a story from the gospels. When we pray the Rosary, we are walking with Jesus through His life; we are praying through the Gospel.
3 — The prayers of the Rosary are Scripture. The Our Father is 100% Scripture. The Hail Mary is 50% Scripture.