I've always been struck by the similarities in St Margaret Mary's revelations of the Sacred Heart and the revelations to St Faustina of the Divine Mercy of this same Heart. I've always felt that the words of Jesus to St. Faustina were a "completion" of the messages He gave to St. Margaret Mary. The words are very similar in nature and I believe were meant for our times. Mark Mallett has written a post called
The Last Effort concerning these two great saints and the cohesiveness of the messages for the world given to them by Jesus himself.