Why Scripture is Essential for Christians
"...Jesus says that if we love him, we will keep his commandments (Jn. 14:15, 21, 23, 15:7, 10). Remember that his words are absolutely necessary for our lives (Jn. 6:68). If we do not do as Jesus says, we may not call him Lord (Matt. 7:21-27). Since Jesus wrote no books, we must trust the writings of his apostles and disciples, the NT books, to meditate our covenant relationship with Jesus.
People often claim to have a personal relationship to Christ, while being uncertain about the role of Scripture in that relationship. But the relationship that Christ has established with his people is a covenant relationship and therefore a verbal relationship, among other things. Jesus' words, today, are found only in Scripture. So if we are to have a covenant relationship with Jesus, we must acknowledge Scripture as his Word. No Scripture, no Lord. No Scripture, no Christ.
(p. 212 - The Doctrine of the Word of God)