God the Father wishes Mary to be the mother of his children until the end of time and so he says to her, “Dwell in Jacob”, that is to say, take up your abode permanently in my children, in my holy ones represented by Jacob, and not in the children of the devil and sinners represented by Esau.
Just as in natural and bodily generation there is a father and a mother, so in the supernatural and spiritual generation there is a father who is God and a mother who is Mary. All true children of God have God for their father and Mary for their mother; anyone who does not have Mary for his mother, does not have God for his father. This is why the reprobate, such as heretics and schismatics, who hate, despise or ignore the Blessed Virgin, do not have God for their father though they arrogantly claim they have, because they do not have Mary for their mother. Indeed if they had her for their mother they would love and honour her as good and true children naturally love and honour the mother who gave them life.
An infallible and unmistakable sign by which we can distinguish a heretic, a man of false doctrine, an enemy of God, from one of God’s true friends is that the heretic and the hardened sinner show nothing but contempt and indifference for our Lady. He endeavours by word and example, openly or insidiously – sometimes under specious pretexts – to belittle the love and veneration shown to her. God the Father has not told Mary to dwell in them because they are, alas, other Esaus.
Saint Louis-Marie Grignion de Montfort
Treatise on True Devotion
(source: Rorate Caeli)