In a nicely nuanced statement, Calvin notes that “there are three modes of insition” [entrance, or grafting] and “two modes of excision.”
The modes of entrance into the covenant are: “the children of the faithful are ingrafted, to whom the promise belongs according to the covenant made with the fathers;ingrafted are also they who indeed receive the seed of the gospel, but it strikes no root, or itis choked before it brings any fruit; and thirdly the elect are ingrafted, who are illuminatedunto eternal life according to the immutable purpose of God.”
As fare as cutting off: “The first are cut off, when they refuse the promise given to their fathers, or do not receive iton account of their ingratitude; the second are cut off, when the seed is withered anddestroyed; and as the danger of this impends over all, with regard to their own nature, it must be allowed that this warning which Paul gives belongs in a certain way to the faithful, lest they indulge themselves in the sloth of the flesh.”
