The church does not offer grace, it is a gift of God.
Ephesians 2:8 For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:
Rom. 5:15 But not as the offence, so also is the free gift. For if through the offence of one many be dead, much more the grace of God, and the gift by grace, which is by one man, Jesus Christ, hath abounded unto many.
There is more than one understanding of the word grace.
8. (Christianity / Ecclesiastical Terms) Christianity
a. the free and unmerited favour of God shown towards man
b. the divine assistance and power given to man in spiritual rebirth and sanctification
c. the condition of being favoured or sanctified by God
d. an unmerited gift, favour, etc., granted by God
So that the Grace of God is mercy. And the grace one receives through communion with the church and the sacraments is divine assistance and sanctification.
Two different things.