Pricking and ruling

The preparation of these pages with pricking and ruling constitutes a true meditation on the cross:

Source: gallica.bnf.fr

Bibliothèque nationale de France, Département des Manuscrits, Latin 2421, fol. 10r.

But what kind of document requires such an effort?

Rabanus Maurus, In honorem sanctae Crucis [De laudibus sanctae Crucis] (f. 1r-45r). — Publius Optatianus Porphyrius, Panegyricus Constantino missus (46-55).
Source: gallica.bnf.fr
Bibliothèque nationale de France, Département des Manuscrits, Latin 2421, fol. 20v.

In Praise of the Holy Cross by Rabanus Maurus

Rabanus Maurus, In honorem sanctae Crucis [De laudibus sanctae Crucis] (f. 1r-45r). — Publius Optatianus Porphyrius, Panegyricus Constantino missus (46-55).
Source: gallica.bnf.fr
Bibliothèque nationale de France, Département des Manuscrits, Latin 2421, fol. 29v.