Catechism of the Catholic Church

This petition is astonishing. If it consisted only of the first phrase, "And forgive us our trespasses," it might have been included, implicitly, in the first three petitions of the Lord's Prayer, since Christ's sacrifice is "that sins may be forgiven." But, according to the second phrase, our petition will not be heard unless we have first met a strict requirement. Our petition looks to the future, but our response must come first, for the two parts are joined by the single word "as." (1425, 1933, 2631)