The Criterion for Distinguishing Between Commands and Prohibitions Regarding Their Original Ruling

Some scholars say: The original ruling for commands is that they are obligatory, except in matters of etiquette and recommended acts, where the original ruling is that they are recommended. The original ruling for prohibitions is that they are forbidden, except in matters of etiquette, where the original ruling is that they are disliked.
So what is the criterion for distinguishing between a command that falls under etiquette and one that does not?
Etiquette refers to what concerns honor and the path upon which the servant proceeds, whereas acts of worship are the worship of Allah (Mighty and Majestic). However, even in acts of worship, there is no specific criterion, and many of these commands in acts of worship are agreed upon by scholars to be recommended. But all of these are issues debated by the scholars of the principles of jurisprudence: Is the command for obligation or for recommendation?Some said: The original ruling is obligation.By the saying of Allah (Blessed and Exalted is He): [Surat al-Nur: 63] Some said: It is for recommendation, because the original ruling for a command is its prescription, and the original ruling is that there is no sin in leaving it, and this is the reality of recommendation. Upon reflection, the issue does not have a specific criterion.