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During the Reformation, Luther did not abandon the rosary, though he shortened the Ave Maria to this form: “Hail Mary, full of grace. The Lord is with thee. Blessed art thou and the fruit of thy womb, Jesus.” In this way he eliminated the plea for Mary to pray for the supplicant. He advised his followers to use the rosary as an aid to meditation.
https://liturgical.wordpress.com/2007/09/29/new-books-what-martin-luther-thought-about-prayer-beads/