In fact, within those four lines of the mnemonic, if you look from a different perspective, the first line "All Swords Return to the Sect" and the third line "Self-Sacrifice" are written clearly and straightforwardly, while the second line "Qi Rushing to Primordial Energy" and the fourth line "Rebirth Acupoint Senior" seem messy and nonsensical.
But in reality, those two seemingly nonsensical lines also have deeper meanings.
In "Qi Rushing to Primordial Energy", "Primordial" refers to "Primordial Energy", and "Energy" corresponds to "Round", indicating some parts in the cultivation of primoridal energy that are not perfect.
Therefore, the overall meaning of this line is to use one's inner strength to attack the imperfect aspects of one's cultivation.
However, it is difficult for most people to have an absolute clear understanding of their deficiencies during cultivation. If they can, they would have found ways to remedy them already, rather than letting them linger.
