Pride Goes Before Destruction
Mr. Obadiah Slope’s enormous pride and haughtiness become evident early in the novel and only worsen as the narrative develops. He foresees no obstacles to winning Mrs. Bold’s affection and feels confident in his ability to woo any women with his wiles. It takes a humiliating slap in the face to send him the message that his wiles are not welcome, and he reacts with rage, not humility. His also loses his sparring match with Mrs. Proudie over the control of Dr. Proudie. His greatest display of pride, his coveting of the deanery without any kind of humble introspection or self-examination to judge his own merits for the position, ultimately ends in his total fall and humiliation. His public character destroyed and all of his ambitions ruined, Mr. Slope perfectly exemplifies the moral of Proverbs 16:18:
Pride goes before destruction,
a haughty spirit before a fall.
The Last Shall Be First
Mr. Harding, on the other hand, the hero of the novel, is Mr. Slope’s character foil (the opposite). Whereas Mr. Slope always seeks his own advancement at all costs and at the sacrifice of any person, Mr. Harding continually turns down offers of advancement within the church and constantly worries about the feelings of others (probably too much, as this endearing foible lands him in an awkward scrape or two). In contrast to Mr. Slope’s arrogance in his self-worth, Mr. Harding is often concerned about whether he would be able to properly fulfill the duties of the positions he is offered – although comically everyone tries to assure him there are almost no duties. Mr. Harding ultimately settles down into a lifetime of humble obscurity, allowing his son-in-law to attain the position of dean instead of himself. On the final page of the book the narrator asks that the reader remember Mr. Harding
not as a hero, not as a man to be admired and talked of, not as a man who should be toasted at public dinners and spoken of with conventional absurdity as a perfect divine, but as a good man without guile, believing humbly in the religion which he has striven to teach, and guided by the precepts which he has striven to learn.
How Delightful is Your Love
Amidst the banality of the church and all its dry tradition, Trollope allows a fresh romance to blossom and calls it a “luxury” that “far  surpasses any other pleasure which God has allowed to his creatures.” The narrator illustrates the beauty of love between a husband and wife by comparing it to the way a stone wall reveals the glory of ivy vines:
[Vines] were not created to stretch forth their branches alone, and endure without protection the summer’s sun and the winter’s storm. Alone they but spread themselves on the ground, and cower unseen in the dingy shade. But when they have found their firm supporters, how wonderful is their beauty; how all pervading and victorious! What is the turret without its ivy, or the high garden-wall without the jasmine which gives it its beauty and fragrance? The hedge without the honeysuckle is but a hedge.
Barchester Tower’s most beautiful illustration of the church (which is the body of Christ) is not in the clergymen or the architecture or the sermons, but in the marriage covenant. Eleanor and Mr. Arabin learn to forgive each other, then pledge a lifelong commitment to each other and enjoy the pleasures of marriage founded on the Christly principles of servanthood, humility and interdependence.