To many, total abstinence is easier than perfect moderation.

[Multi quidem facilius se abstinent ut non utantur, quam temperent ut bene utantur.]

Augustine of Hippo (354-430) Christian church father, philosopher, saint [b. Aurelius Augustinus]

On the Good of Marriage [De Bono Conjugali], § 25 (AD 401)
    (Source)

(Source (Latin)). Alternate translations:

Many indeed with more ease practice abstinence, so as not to use, than practice temperance, so as to use well.
[tr. Cornish (<1885)]

Many indeed find it easier to abstain from making use of them than to control their use and use them properly.
[tr. Kearney (1999)]

Complete abstinence is easier than perfect moderation.
[E.g.]