Through the gift of this grace of God that was in him, St. Francis was not only rapt in God in ecstatic contemplation, but he was also sometimes consoled by visitations of angels.
One day while he was thinking about his death and the state of his Order when be was no longer alive, and he was saying, “Lord God, after my death what will happen to Your poor little family which in Your kindness You entrusted to this sinner? Who will console them? Who will correct them? Who will pray to You for them?” and similar words, an angel sent by God appeared to him and consoled him by saying: “I tell you on behalf of God that your Order will last until Judgment Day. And no one, no matter how great a sinner he is, will fail to obtain mercy from God if he has a heartfelt love for your Order. And no one who from malice persecutes your Order will be able to live long. Moreover, no one in your Order who is very evil and who does not amend his life will be able to persevere in the Order. Therefore do not grieve if you see some friars in your Order who are not good and who do not observe the Rule as they should. And do not think then that your Order is declining, because there will always be very many in it who will perfectly observe the Gospel life of Christ and the purity of the Rule. And immediately after their earthly life they will go to eternal life without passing through Purgatory at all. Some will live the life less perfectly, and they will be purified in Purgatory before they go to Paradise, but the period of their purgation will be entrusted to you by God. But do not worry about those who do not keep your Rule at all, says God, because He does not care about them.”
Now why those holy Stigmata were imprinted on St. Francis is not yet entirely clear. But as he himself told his companions, this great mystery is reserved for the future.
Brother Leo told this account to Brother James of Massa, and Brother James of Massa told it to Brother Ugolino di Monte Santa Maria, and Brother Ugolino, a good and trust-worthy man, told it to me who am writing.
During that seraphic apparition Christ, who appeared to St. Francis, spoke to him certain secret and profound things which the Saint was never willing to reveal to anyone while he was alive, but after his death he revealed them, as is recorded further on. And these were the words: “Do you know what I have done?” said Christ “I have given you the Stigmata which are the emblems of My Passion, so that you may be My standard-bearer. And as I descended into Limbo on the day when I died and took from there by virtue of these Stigmata of Mine all the souls that I found there, so I grant to you that every year on the day of your death you may go to Purgatory and by virtue of your Stigmata you may take from there and lead to Paradise all the souls of your Three Orders, that is, the Friars Minor, the Sisters, and the Continent, and also others who have been very devoted to you, whom you may find there, so that you may be conformed to Me in death as you are in life.”
Source: Little Flowers of St. Francis