As grace was infused into Adam from the first moment of his creation, so that he never had experience of his natural poverty till sin reduced him to it; so was grace given from the first in still ampler measure to Mary, and she never incurred, in fact, Adam's deprivation. She began where others end, whether in knowledge or in love. She was from the first clothed in sanctity, sealed for perseverance, luminous and glorious in God's sight, and incessantly employed in meritorious acts, which continued till her last breath. Hers was emphatically "the path of the just, which, as the shining light, goeth forward and increaseth even to the perfect day"; and sinlessness in thought, word, and deed, in small things as well as great, in venial matter as well as grievous, is surely but the natural and obvious sequel of such a beginning. If Adam might have kept himself from sin in his first state, much more shall we expect immaculate perfection in Mary. ("Discourses to Mixed Congregations." pp. 351-5.) - Blessed John Henry Newman
http://origin-rh.web.fordham.edu/halsall/mod/newman-mary.asp