"I am a nobody, I am a small rope, a tiny ladder, the tail end, a leaf."
Here we see why God chose Juan Diego to receive the vision and message of Guadalupe, as the Holy Spirit spoke through Saint Paul:
 But the foolish things of the world hath God chosen, that he may confound the wise; and the weak things of the world hath God chosen, that he may confound the strong.  And the base things of the world, and the things that are contemptible, hath God chosen, and things that are not, that he might bring to nought things that are:  That no flesh should glory in his sight.  But of him are you in Christ Jesus, who of God is made unto us wisdom, and justice, and sanctification, and redemption:Happy Feast of Our Lady of Guadalupe!
 That, as it is written: He that glorieth, may glory in the Lord (1 Cor 1:27-31).
PS: Juan Diego, a layman baptized and catechized by Franciscans, who became celibate living in a hermitage and received the Holy Eucharist thrice a week, was very likely a Third Order Franciscan.