Is abandoning the voluntary prayers (Sunnah) of Dhuhr and Asr after having previously committed to them considered a shortcoming or a sin against Allah?

There is no sin in abandoning supererogatory prayers, nor is there punishment for it in the Afterlife, for the Prophet, peace and blessings be upon him, said: "Is there anything else obligatory upon me?" He replied: "No, unless you perform supererogatory prayers."

However, they are among the greatest acts of drawing closer to Allah and compensate for any deficiencies in the obligatory prayers. They also have a great impact on the rectification of the heart. The Prophet, peace and blessings be upon him, said: "Prayer is the best subject; whoever can do much of it, let him do so."

It is recommended to maintain the supererogatory prayers of Dhuhr, the minimum of which is two rak'ahs before it and two rak'ahs after it, and the best is four before it and two after it.

As for Asr, it does not have a confirmed Sunnah (supererogatory prayer), but it is recommended to pray two or four rak'ahs before it, for the Prophet, peace and blessings be upon him, said: "May Allah have mercy on a person who prays four rak'ahs before Asr."