From the Diary of St. Faustina:
411-Often during Mass, I see the Lord in my soul; I feel His presence which pervades my being. I sense His divine gaze; I have long talks with Him without saying a word; I know what His divine Heart desires, and I always do what will please Him the most. I love Him to distraction, and I feel that I am being loved by God. At these times when I meet with God deep within myself, I feel so happy that I do not know how to express it. Such moments are short, for the soul could not bear it for long, as separation from the body would be inevitable. Though these moments are very short, their power, however, which is transmitted to the soul, remains with it for a very long time. Without the least effort, I experience the profound recollection which then envelops me–and it does not diminish even if I talk with people, nor does it interfere with the performance of my duties. I feel the constant presence of God without any effort of my soul. I know that I am united with Him as closely as a drop of water is united with the bottomless ocean.