I hadn't seen this kind of thing for so long that I forgot that it existed. Then I saw it again, recently. Bad practices just never seem to go away. The minister about to read from the Scriptures first pauses, and then takes a few moments to explain to the people what the Scriptures are about to say to them. No doubt this device is supposed to help the listeners tune in, as it were, and pay closer attention; then they will retain what they have heard all the more. So what's wrong with that, you ask? Nothing, really, if what you are about to read is on the same level of significance. But if what you are about to read happens to be the Word of the Living God, then an introduction gains for itself the unsavory effect, however unintended, of reducing the significance and power of what follows. Imagine, if you will, having someone introduce a speaker at a conference, or the President of the United States, or any dignitary, by not only telling us the person's credentials, but also by telling us what he is about to say. It does not highlight, but denigrates, the importance of the speech itself. How much more is this the case when it comes to Sacred Scripture. What you subliminally but very clearly say when you preface the words of God with your own explanation of them is that your words and His words are on the same level; or worse, that your words are on a higher level, necessary to explain His. When on the contrary the explanation comes in the sermon, as it should, then you are leaving the Scriptures alone as the authority on which you preach.
When we say that the Word of God is like a double-edged sword, that it has the power of salvation, that it is full of the Holy Ghost, we belie what we say if we feel constrained by a need to engage in personal ad-lib introductions.
Consider the introduction John the Baptist gave for Jesus: He introduced Him with the words of the prophet: Prepare ye the way of the Lord. So also, when we introduce the Holy Gospel, we do so by the words of Moses and the Prophets (Old Testament reading) and the words of the Apostles (Epistle reading). In this case we use God's words to introduce God's words, and then, as everyone rises from his seat for the Gospel, we acknowledge that the most significant and powerful words of all are the words of Christ.