Catechism of the Catholic Church §112 — excerpt
Be especially attentive "to the content and unity of the whole Scripture". Different as the books which compose it may be, Scripture is a unity by reason of the unity of God's plan, of which Christ Jesus is the center and heart, open since his Passover.
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: St. Thomas Aquinas, Expos. in Ps. 21, 11