Quote by Father Evan on the Theotokos (Mary) and sinlessness

Sin is to miss the mark (Amartia, an archery term). Sin is anything that would offend or come between or break the bond of love between ourselves and God.... Sin is the breaking of a relationship. So the Church asks the question, we put it out there... did Mary every break her relationship with Jesus? And the answer is no, she never departed from His side.



Source:

http://ancientfaith.com/podcasts/orthodoxylive/march_17_2013