12 The host was given over [to it] together with the continual [offering] through disobedience; and it cast down truth to the ground, and it did [its pleasure] and prospered.
an army was given over – Satan was given an “army of angels,” who were cast down from heaven in verse 10.
to oppose the daily sacrifices – literally to oppose “the continual offering of Christ’s blood.” The army of demons opposed the sacrifice of Christ’s blood that spoke for the saints. The saints lost the assurance that the Church had the authority to wash away their sins through baptism when the holy spirit departed. Therefore, Satan and his angels accused the saints. The work of Satan is described in Revelation 12:10, “he who accuses them before our God both day and night.” But John will tell us that the saints “overcame by the word of their testimony.” The saints overcame the accusation of Satan through their faith.
and he cast truth to the ground – through the working of his demons in the spiritual world, and through the Bishop of Rome in the natural world.
And he did all this and prospered – see Dan 7:21 “and prevailing against them” (the saints).