Knowledge of the biblical period is mostly from literary references in the Bible and post-biblical sources. Religion and music historian Herbert Lockyer, Jr. writes that "music, both vocal and instrumental, was well cultivated among the Hebrews, the New Testament Christians, and the Christian church through the centuries." He adds that "a look at the Old Testament reveals how God's ancient people were devoted to the study and practice of music, which holds a unique place in the historical and prophetic books, as well as the Psalter." The music of religious ritual was first used by King David, and, according to the Larousse Encyclopedia of Music, he is credited with confirming the men of the tribe of Levi as the "custodians of the music of the divine service," .