General Blasphemy
The devil delights in blasphemy, and is said to be present at any such act: Dr Faustus only manages to summon a demon by incidentally blaspheming in frustration. Blasphemy is a contractual obligation when for witches making a pact with the devil: ‘the devil asks whether she will abjure the Faith, and forsake the holy Christian religion and the worship of the Anomalous Woman (for so they call the Most Blessed Virgin MARY), and never venerate the Sacraments’ (Malleus Part II, Question 1, Chapter 2). In so doing, the witches are angering God, and hence pleasing their master, the devil.
It may come as a surprise to learn that witches were still known to attend Mass, despite their allegiance to Satan. Mass however gave them an opportunity to please their master: ‘they are bound to observe certain other abominable ceremonies at the command of the devils, such as to spit on the ground at the Elevation of the Host, or to utter, either verbally or otherwise, the filthiest thoughts’ (Malleus Part II, Question 1, Chapter 4). This particular claim is especially dangerous: even regular churchgoers, not merely those known to skip Mass, were under suspicion of witchcraft.
Witches (thus especially women) were to be observed closely when taking the Eucharist: ‘they receive the Lord’s Body under their tongue instead of on the top… the reason is that they never wish to receive any remedy that might counteract their abjuration of the Faith… and because in this way it is easier for them to take the Lord’s Body out of their mouths so that they can apply it… to their own uses, to the greater offence of the Creator’ (Malleus Part II, Question 1, Chapter 5). Other sacred objects could also be stolen and defiled for black magic.