From the Catechism of the Catholic Church
http://www.vatican.va/archive/ccc_cs...m/p4s1c2a2.htm
2677 By asking Mary to pray for us, we acknowledge ourselves to be poor sinners and we address ourselves to the "Mother of Mercy,"
the All-Holy One. We give ourselves over to her now, in the Today of our lives. And our trust broadens further, already at the present moment, to surrender "the hour of our death" wholly to her care. May she be there as she was at her son's death on the cross. May she welcome us as our mother at the hour of our passing38 to lead us to her son, Jesus, in paradise.