Macbeth:

Besides, this Duncan
Hath borne his faculties so meek, hath been
So clear in his great office, that his virtues
Will plead like angels, trumpet-tongued, against
The deep damnation of his taking-off;

Besides, Duncan has born his faculties so gentle, has been so clear in his great office, that his virtues will be emotionally appealed like angles. And the angles are playing trumpets against the injustice of the killing of him.

Macbeth:

But in these cases
We still have judgment here, that we but teach
Bloody instructions, which, being taught, return
To plague th’ inventor:
But in this world there is still punishments for those who commit crimes like this. And this will teach bloody instructions (violence), which, when teach this violence, will come back as violence to us teachers.