For I know that this shall fall out to me unto salvation, through your prayer and the supply of the Spirit of Jesus Christ, According to my expectation and hope; that in nothing I shall be confounded: but with all confidence, as always, so now also, shall Christ be magnified in my body, whether it be by life or by death. (Philippians 1:19-20)
Was St. Paul wrong when he thought that these prayers would help him? Is it a bad thing to ask a Christian to pray for you? St. Paul didn't think so.
He's our only ... intercessor.
Let's test this doctrine according to the Scriptures:
1 I desire therefore, first of all, that supplications, prayers, intercessions and thanksgivings be made for all men:
2 For kings and for all that are in high station: that we may lead a quiet and a peaceable life in all piety and chastity. (1 St. Timothy 2)
And also, it shouldn't take an apparition calling itself "Mary" to point the way to Jesus. The apparition is the one that ends up with all the attention.