(You can read the German version here).
The book of Revelation describes in the tenth chapter a mighty angel "wrapped in a cloud, with a rainbow over his head" (Rev 10:1) descending to the place where St. John is. This angel had a small book open and, to his amazement, the voice from heaven asks him to eat it: "Take it and devour it, it will make your insides bitter, but in your mouth it will be sweet as honey". (Rev 10:9).
It is not the only case. In the Old Testament, the book of Ezekiel, narrates a similar episode when in the third chapter the Spirit, within him, asks him to eat the scroll held by a hand before him: He unrolled it before my eyes: it was written on the front and on the back; it had written, "Lamentations, groanings, and woe." And he said to me, "Son of man, eat what is offered to you; eat this roll, and then go and speak to the house of Israel." And I opened my mouth, and he made me eat the roll, and said to me, "Son of man, feed and be satisfied with this roll that I give you." I ate it, and it was in my mouth sweet as honey. Then he said to me, "Son of man, go to the house of Israel and speak to them in my words." (Ezek 2:10 - 3:3)
What these indications seem to say is the need to interiorize the Word of God that we are going to transmit. We give of our own because we have made our own what we give, contemplata aliis tradereThe scribe of the Kingdom of Heaven is "like a man, master of his own house, who brings out of his treasure new things and old things" (Mt 13:52), the old things are the eternal truths, the new things are the human and changing realities, but the important thing is that the place from which he brings out the old and the new is his treasure, his own soul.
The reading of the Word of God, meditation and contemplation are the beginning of preaching. Through this intimate contact the Lord plants the seed of eternal truth in our soul, a seed that, like a mustard seed, must grow into a leafy tree. Christ promised that He, the Spirit of Truth, "will guide you into all truth" (Jn 16:13) and He, the Advocate, does so by introducing us into a school that produces fruits of holiness in our lives and gives supernatural efficacy to our preaching. As Francisca Javiera de Valle explains in her Decenary: "This Divine Master places his school in the interior of the souls who ask him and ardently desire to have him as their Master. He exercises there this office of Master without the noise of words and teaches the soul to die to itself in everything, in order to have life only in God. The way this skillful Master teaches is very consoling; and he does not want to set up a school anywhere else to teach the ways that lead to true holiness, but in the interior of our soul; and he gives himself such art... and skill... to teach..., he is so skillful and so wise, so powerful and subtle, that, without knowing how, one feels, after a short time of being with him in this school, all changed. Before entering this school, I was rude, without ability, very clumsy to understand what I heard preached; and entering it, how easily one learns everything; it seems as if they transmit to one even in one's entrails the science and the ability that the Master has". (Decennial, 4th day, Consideration).
It is now understood that it is holiness of life that makes our preaching alive and not boring because it is a Life that we transmit with our life. It is understood that saints who hardly knew how to read, like St. Catherine of Siena, were so instructed in this school that they were declared Doctors of the Church; they could perfectly well say, like St. John: "What we have seen and heard, we proclaim to you so that you also may be in communion with us". (Jn 1:3)
Therefore, before talking about what we understand in that way, we should lower our heads with humility to recognize that we have no idea and instead of giving advice to the staff, we should ask the Lord in prayer, as the apostles did: edissere nobis parabolam(Mt 13:36), "Master, teach us the parable", so that I, understanding, contemplating, allowing myself to be instructed by you, may in turn, giving of my own, which is yours, teach my people.
With many such parables he expounded the word to them, adapting it to their understanding. "He expounded all things to them in parables, but to his disciples he explained everything in private" (Mk 4:24). Here is the quid of the matter. This is what it means to take God seriously.
