Think of things like Scapulars and other devotions as being similar to marriage. A couple say on their wedding day that they will stay together ‘until death do us part’, and they exchange rings, which they wear presumably for the duration of the marriage. Then they do other things as well to reaffirm that marriage bond - live together, give each other gifts, have children together, say ‘I love you’ a lot, etc etc.
The promises and the ring and all the other actions don’t of themselves guarantee that the marriage will last, or succeed. Nor do they actually make the marriage. It works the reverse way. FIRST comes the desire of the two people to spend their lives with each other and make the marriage committment.
The promises are their way of publicly affirming this desire to committ, the rings and all the rest are their way of reminding themselves and each other of their committment, and showing it to everyone else as well. All of this taken together is what forms the marriage and makes it work and succeed.
So with Scapulars, First Fridays etc. FIRST comes the love of Jesus and Mary for us and their desire to seek and facilitate as much as possible the salvation of all souls. THEN come their promises, which are open to all those who love them and are devoted to them.
THEN comes the pre-existing love and commitment and trust of those who choose to accept those promises. When these people then do the devotion or wear the Scapular they have the constant visible reminder and reaffirmation of their commitment. All this together makes them so much more disposed to being saved.
The material that comes with each Brown Scapular (they each come with a little leaflet) starts off by stating that it is not a magic charm, nor does it of itself guarantee salvation. The fact is by agreeing to wear it one is making promises in regards to their prayer life, to living chastely according to their single or married state in life, and other things.
It is the fulfilment of these conditions and the work put in by the wearer that makes them more disposed and more receptive to the graces of God that lead to salvation, not the mere wearing of the bit of cloth.
Likewise with the First Friday devotions. These require attendance at Mass and reception of Communion on the First Fridays of NINE consecutive months. For most people this will require sacramental confession at least once in each of these months.
This is quite a lengthy committment - nine solid months! One starts off with quite a high level of devotion and commitment to even begin, and to go through with it can’t help but increase this fantastically.
So the promises aren’t just promises out of thin air - remember they’re contingent on certain action on behalf of those seeking to take advantage of them. The action in itself predisposes people to a beneficial outcome spiritually.
