Medieval proselytizers advised defending reasonableness over attacking the rival faith

Evidence

It was better, he advised, not to begin immediately from divine principle, but to show them one Christian law, and to be brief in all things. It was easier to show Islam false, than Christianity true. What was necessary was only to defend the reasonableness of the faith, to accept the unity of God, and to insist also on His simplicity; to point out that it does not follow that the discretion of Persons is untrue because it is incomprehensible. — Norman Daniel, Islam and the West, 1011

Categorization

• XREF: connects to: Medieval theologians reframed Scripture to justify killing infidels in war