Both Uses of

sanction
in
The Narrative of the Life of Frederick Douglass

Prior to his conversion, he relied upon his own depravity to shield and sustain him in his savage barbarity; but after his conversion, he found religious sanction and support for his slaveholding cruelty.†
Chpt 9 *

Definitions:

(1) (sanction as in: cannot sanction such behavior)
formal approval

Ironically, this word has contradictory meanings that are frequently used. When selecting words for an audience who may not be sure of this word's contextual meaning, consider substituting a word like endorse for this sense of sanction.
(2) (sanction as in: sanctions against them)
formal penalty

This word has contradictory meanings that are frequently used. When selecting words for an audience who may not be sure of this word's contextual meaning, consider substituting words like penalize for this sense of sanction.