Christadelphians accept the 66-book Protestant canon as the complete and authoritative Word of God. They are a strongly text-focused movement — extensive personal Bible study is expected of all members, and ecclesial exhortations are expositions of Scripture. The Bible is the sole authority for Christian belief and practice; no tradition, creed, or human authority may override it.

The deuterocanonical books are not considered inspired Scripture by Christadelphians. While they may be read for historical interest, they carry no doctrinal weight. This is consistent with the Protestant tradition and with the Christadelphian emphasis on testing all teaching by the canonical Scriptures.

Christadelphians have historically produced extensive Bible study aids, commentaries, and publications (such as The Christadelphian magazine, founded by Robert Roberts in 1864) focused on Bible exposition. Their approach is strongly word-based and exegetical, with theological claims expected to be backed by detailed biblical argument. The sufficiency and perspicuity of Scripture — its adequacy and clarity for all matters of faith — is foundational to the Christadelphian self-understanding as a community gathered around the plain teaching of the Bible.