This is an extract from the book Al-Waadih Fee Usool ul-Fiqh by Muhammad Hussein Abdullah available to purchase from Amazon.
In respect to the Adillah (evidences) used as proof by those who say that the Seeghat ul-Amr indicates Al-Wujoob (the obligation), then they have erred in their manner or process of deduction. That is because these evidences are related to the obedience to the command (Al-Amr) and disobedience to it whilst they are not related to the Seeghat ul-Amr (form of the command). The Amr (command) of Allah is Waajib (obligatory) to obey and disobedience to it is Haraam.
Obedience to the command is by not rebelling against it and obedience to the command is fulfilled in accordance to what Allah Ta’Aalaa has commanded. Consequently, if His command was Jaazim (decisive) then its obedience is Waajib in accordance to what has been commanded; undertaking the action is Waajib (obligatory) and the person would be disobedient if he did not undertake the action. This is represented in the Fard and Waajib. It is like His command to perform the obligatory Salawaat (prayers).
And if the command (Amr) was Ghair Jaazim (indecisive), obedience to it (in respect to being a command) is obligatory, as it has been commanded in its indecisive form. If the person undertook the action he would earn reward and if he submitted to the command but did not undertake the action that had been commanded, he would not have sinned, would not be disobedient (‘Aasiy) and would not be punished. This is the Mandoob like the Sunan prayers.
If, however he was to rebel against this command, deny it, not submit to, not accept this Mandoob nor acknowledge it, then he would be ‘Aasiy (disobedient) and going against the command of Allah. That is because the One who commanded the Waajib is also the One who commanded the Mandoob. Therefore, it is obligatory to submit to the Mandoob being from Allah even if he did not undertake or perform it.
Allah (swt) said:
إِنَّ اللَّهَ يَأمُرُ بِالعَدلِ وَالإِحسانِ
“Verily, Allah commands justice and the best conduct”
So, Allah Ta’Aalaa has commanded justice and He has commanded the best conduct. However, the command for justice (Al-‘Adl) is one of obligation (Al-Wujoob) whilst the command for the best conduct (Al-Ihsaan) is one of recommendation (An-Nadb) even though they have come in the text as a single command and within one single text. That indicates that the mere Amr (command) does not indicate the obligation but rather it could indicate the Wujoob, the Nadb or the Ibaahah (obligation, recommendation or permissibility).
Consequently, the obedience to the Amr (command) and disobedience to it does not indicate undertaking the action that has been commanded or refraining from undertaking it. Rather, it indicates to submitting to the command and obedience to it upon the basis that it was commanded in terms of it being obligatory, recommended or permissible.