Dear saints, let us pray that the saints would diligently learn the hymns according to their category, content, central thought, focus, sensation, taste, and tune so that they may select appropriate hymns in the meetings, especially in the Lord’s table meeting (Col. 3:16; see Hymns, Table of Contents).
In order to call the appropriate hymns in the table meeting, we need to learn to know the hymns first in their categories. The table of contents in our hymnal can help us with this, since it categorizes all the hymns. Then we need to read and even to study the contents of the hymns. We also need to find out the central thought, the focus, of each hymn. Finally, we need to know the hymns in their sensation and taste. Each hymn has its own sensation, so it has its own taste. When you know the hymns in these four aspects—in their categories, contents, focus, and sensation and taste—you know the hymns thoroughly. (Collected Works of Witness Lee, 1979, vol. 2, “Basic Lessons on Service,” Lesson 4)
More details via Beseeching.org, day 408.