On the Sermon
Then the bishop delivers a sermon to the people, for after Christ made himself known to the people by the apostles, he himself began to preach to all. The bishop instructs the people on penance, faith, and confession, for Christ taught penance, faith in God, and the remission of sins by confession and baptism.
After this the people sing Kyrie eleison and the clergy sing Credo in unum Deum ; for they affirm that they believe what the deacon read and what the bishop preached. Thus, after Christ and the apostles taught the people, they sounded praises to God on account of the faith received.
Meanwhile, the Gospel-book is carried through the choir with incense, and extended for each one to kiss, for the apostles carried Christ, the odour of life, through the world, and proffered eternal peace to all peoples through his word .
 Cf. Jungmann (vol. 1, pg. 472). It seems Honorius may be referring to the genre of “Credo-songs” sung by the people in lieu of the Credo itself, and using the refrain Kyrie eleison. Since it was often too much to expect the people to chant the whole text of the Creed in Latin, various substitutes were contrived, to be sung while the clergy sang the Credo. Sometimes these songs were even in the vernacular:
“For Germany Berthold of Regensburg (d. 1272) mentions with praise the practice he found in several places where the people joined the “Credo” by singing a German song which he cites as follows: Ich gloube an den Vater, ich gloube an den Sun miner frouwen sant Marien, und an den Heiligen Geist. Kyrieleys.”
 Jungmann explains the origin of this practice in the ancient papal stational liturgy:
“When the Gospel ended it was customary in the Roman stational services for a subdeacon to take the book (not with bare hands, however, but holding it super planetam), and to bring it around to the attending clergy to be kissed before it was returned again to its casket, sealed and brought back to its place of safekeeping.
In countries of the North, the people were, for a time, permitted to share in this veneration of the Gospel book” (Missarum Sollemnia, vol. 1, 449).
In a footnote, he continues: “According to WIlliam of Hirsau […] the priest at a private Mass kissed the book after the reading, then handed it to the Mass-server et aliis communicare volentibus to be kissed.”
Deinde episcopus sermonem ad populum facit, quia postquam Christus populo per apostolos innotuit, ipse omnibus praedicare coepit. Episcopus populum de poenitentia, et fide, et confessione instruit, quia Christus poenitentiam, et fidem in Deum et remissionem peccatorum per confessionem et baptisma docuit. Post haec populus Kyrie eleyson, et clerus Credo in unum Deum, cantant; quia quod diaconus legit, et quod episcopus praedicavit se credere affirmant. Ita postquam Christus et apostoli populum docuerunt, fide recepta, laudes Deo personuerunt. Interim Evangelium cum incenso per chorum defertur, et singulis ad osculandum porrigitur; quia apostoli Christum (odorem vitae) per mundum portaverunt, et cunctis gentibus per verbum eius pacem aeternam praebuerunt.