Thwe Westminster Confession is not consistent with the scripture itself. For example, human authoriship as well as divine inspiration are scriptural facts; the selection of books that the Confession considers inspired is arbitrary work of the authors of the Confession, tracing back to Luther and not to any divine source; the notion that Church follows scripture is nowhere in the scripture, yet it obviously is one of those things "necessary to be known, believed, and observed for salvation".
Your opening quotes from the scripture do nothing to support the fantasies in the Confession or rebut the Elder's analysis. John 6:35 speaks of the person of Jesus and not of the scripture; Matthew 4:4 does not make the distinction between written word and any other word of Christ, of which, scripture tells us not all are written down (John 21:25)
Doesn't describe at all how I construe Scripture and/or reality.