What does pause mean in ancient poetry? Why not use commas, or not at all?

In ancient times, there were no punctuation marks. In fact, pause is a clause symbol, which will naturally be clicked after a sentence is written. Modern punctuation marks come from the west. Words were not punctuated at first, but now punctuated versions are added by modern people. Up to now, many words are still inconclusive, such as "just like a river flowing eastward" and "just like a river flowing eastward", and there is no unified model, which is related to the lack of punctuation marks in ancient writing. The pause between the lines you see now actually means that the meanings of these two sentences are coherent, but they are artificially separated for easy reading. If you like, they are the same when read together, and the meaning has not changed. In addition, this is called sentence reading (sound teasing).