The Eucharist is a powerful sacrament, one that brings us closer to God, inviting his presence into our very body.
St. John Chrysostom knew this keenly and spoke in one his homilies of the Eucharist’s power to drive away demons.
Let us then return from that table like lions breathing fire, having become terrible to the devil; thinking on our Head, and on the love which [Jesus] has shown for us.
Chrysostom explains why we become “terrible to the devil” after receiving Holy Communion.
This blood, if rightly taken, drives away devils, and keeps them afar off from us, while it calls to us Angels and the Lord of Angels. For wherever they see the Lord’s blood, devils flee, and Angels run together. This blood poured forth washed clean all the world … This blood is the salvation of our souls, by this the soul is washed, by this is beautiful, by this is inflamed, this causes our understanding to be more bright than fire, and our soul more beaming than gold; this blood was poured forth, and made heaven accessible.
It should come as no surprise that the devil will often lead people away from Mass and receiving Holy Communion, doing all that he can to influence a person to abstain from the Sunday Eucharist.
This is also why exorcists advise people feeling oppressed by demons to receive the Eucharist frequently.
If you want to fend off spiritual attacks, go to Mass and receive Jesus worthily, inviting him into your body and soul to drive away any evil presence still lurking there.