but this does not mean that every addition, omission, or doubt entails the prostration; rather, it depends on the details that follow.
The causes for the prostration are three:
- Addition.
- Omission.
- Doubt.
“Not in the case of deliberate action, whether in an obligatory or voluntary prayer …”
His statement, “Not in the case of deliberate action,” means that it is not prescribed when something is done deliberately. This is because, if the deliberate act consists of abandoning an obligation or an essential pillar, the prayer is invalid, and the prostration of forgetfulness cannot remedy it. If it consists of abandoning a sunnah, then the prayer is valid, and there is no need to make up for it through the prostration of forgetfulness. Some scholars, however, mentioned that if someone makes an addition out of ignorance, the prostration of forgetfulness is prescribed for him.
His statement, “whether in an obligatory or voluntary prayer,” means that it is prescribed—whether obligatorily or recommendedly—in both obligatory and voluntary prayers, provided that the prayer includes bowing and prostration. This excludes the funeral prayer, for the prostration of forgetfulness is not prescribed in the funeral prayer, since it contains neither bowing nor prostration. So how could it be remedied by prostration? Every prayer that includes bowing and prostration, however—whether obligatory or voluntary—may be remedied by the prostration of forgetfulness.
If someone were to ask: “Do you hold that the prostration of forgetfulness is obligatory in a voluntary prayer if one leaves out one of the prayer’s obligatory elements?”
The answer is: Yes, we hold it to be obligatory.
If he then asks: “How can you make something obligatory in a voluntary prayer when voluntary prayer is not obligatory in the first place?”