Stir up our hearts, O God

In his This Day, A Wesleyan Way of Prayer, Laurence Stookey includes this prayer for Advent that comes from the Galesian Sacramentary, ca 500.:

Stir up our hearts, O God,
to prepare ourselves to receive your Son.
Grant that when he comes and knocks
he will not find us sleeping in sin,
but awake to righteousness,
endlessly rejoicing in his love.
So purify our hearts and minds
that we may be ready to receive
his promise of life eternal. Amen.