That which is utterly detestable in the sight of God, particularly sin and idolatry. Daniel predicts the establishment of an "abomination that causes desolation" on the temple mount and Jesus Christ reiterates this prophecy.
Sin is an abomination
God detests it
See also
The abomination of Babylon the Great
Idolatry is an abomination
Moses warns the Israelites against the idolatry of the Canaanites:
The idolatry of Solomon's latter years:
idolatry in the temple
Unclean animals are an abomination
The abomination that causes desolation
pp Mk 13:14-19