Horatius Bonar emphasizes the significance of the 'hidden manna' promised to those who overcome, as mentioned in Revelation 2:8-17. He discusses the Church in Pergamos, which, despite its flaws, is encouraged with the promise of divine sustenance and rewards for perseverance in faith. The hidden manna symbolizes Christ Himself, representing the eternal nourishment and glory awaiting believers, contrasting with the temporary sustenance of the wilderness. Bonar highlights that true faith involves struggle and conflict, and the hidden manna serves as a reminder of the spiritual food that sustains the redeemed in their journey towards eternal life. Ultimately, this hidden manna is a promise of Christ's glorified presence, offering everlasting nourishment to the faithful.