The word for this teaching means, plainly, the sung. Singing, as an act, belongs to gladness rather than grief — no one breaks into song from the bottom of despair. That small fact about the name turns out not to be incidental. The entire eighteen books are built to make good on it.
Look at where the teaching itself begins and ends, and the shape becomes hard to miss. The first real words spoken are not comforting — they are corrective: you have grieved over what did not call for grief at all. That is the opening move of the whole instruction, before a single doctrine of action, love, or knowledge has been laid down. And at the very close of the eighteenth book, after everything else has been said, the last direct instruction is two words: do not grieve.
Between those two points, the argument only ever really takes one shape, repeated in different registers: here is why the thing you believed gave you grounds for sorrow does not, once it is actually looked at. Sometimes the ground given is the nature of the self, sometimes the workings of action, sometimes the presence of the divine in ordinary things — but the destination each time is the same removal of an unnecessary weight, not a new weight added in its place.
And what is offered instead of the grief is named directly, twice: freedom from sorrow, and the arrival of joy. These are not treated as two separate prizes, one for effort and one for luck. They read as the same relief, seen from two sides — the way the end of pain and the beginning of ease are, in practice, nearly impossible to tell apart. A teaching that opens by correcting grief and closes by forbidding it has told you, as plainly as it ever tells you anything, what it thinks it is actually for.