We have the ten Commandments, the Lord' Prayers. In short the entire bible is important.
the Bible
The writings of the Church Fathers, The writings of St. Thomas Aquinas, The writings of CS Lewis, The writings of Alexander Solzhenitsyn.
The Bible very simply.
The Holy Bible, the writings of the Church Fathers, & various other writers such as St. Thomas Aquinas.
The most important text for Christianity is the Bible itself and for Bible scholars the ancient manuscripts and texts used to create accurate translations of the Bible including the original manuscripts (e.g. Codex Vaticanus 340 AD), Septuagint, Masoretic text, Dead Sea scrolls, and similar ancient text. In addition to the Bible and original manuscripts there is a plethora of writings from the early church fathers (Ignatius, Origen, Athanasius, Augustine, etc.) and doctors of the church (Thomas Aquinas, etc.). Important modern Christian writings including the writings of C.S. Lewis and G.K. Chesterton.
The Roman historian Tacitus called Christianity a living torch. He also used the words Christ and Christians in his writings.
If the Lord that you speak of is Jesus the Christ, then yes, he had brothers and sisters. One of these, James, was an important apostle who helped spread the new idea of Christianity to the world near Jerusalem. James' more important writings are included in the Holy Bible.
The bible!
Christianity. Music is important in Christianity to sing praises to the Lord.
A number of religions developed out of Christianity. The most important of these is Islam.
cow/pigs/bacon
The Bible.