The Collect for Purity

(This "collect", or liturgical prayer, goes back
to the First Millennium of Christian worship.
This version is translated from the Latin text
found in the Leofric Missal,
in the collections of Oxford University.)

GOD,
to whom every heart lies open,
and every desire is told,
and no secret remains hidden,
cleanse our hearts' schemings
by infusion of the Holy Spirit,
that we may merit
to love You completely
and to praise You worthily.
Through Christ our Lord,
in the unity of the same Holy Spirit,
Amen.