I have been reading The Cloud of Unknowing. And I wanted to share the prayer it starts with, which is also the Collect for Purity that starts the Anglican Eucharist:

Almighty God,
to whom all hearts are open,
all desires known,
and from whom no secrets are hidden:
cleanse the thoughts of our hearts
by the inspiration of your Holy Spirit,
that we may perfectly love you,
and worthily magnify your holy name;
through Christ our Lord.
All Amen.