Is it permissible for me to buy groceries for workers with the value of an oath expiation (kaffarat al-yamin) sufficient for them for a month, knowing that the type of food is not what I usually eat and the value is less, or must I buy them from what I usually eat?

The expiation for an oath becomes obligatory through one of three things: freeing a slave, feeding ten poor people, or clothing them. Whoever cannot find these should fast for three days. It is not permissible to pay it in cash according to the majority of scholars.

The expiation can be given as food in one of two ways: 1. Preparing enough food (lunch or dinner) for ten poor people and inviting them. 2. Giving a specific amount, which is approximately 1.5 kg of rice or wheat for each poor person, with the recommendation of adding a condiment or meat to complete the feeding.

This estimation is based on juristic reasoning and is not explicitly defined in Islamic law. It is analogized to the expiation for Hajj mentioned in the hadith of Ka'b ibn Ujrah, where the Prophet, peace and blessings be upon him, ordered feeding half a sa' to each poor person.

Therefore, giving the expiation as food equivalent to an average lunch or dinner meal, or 1.5 kg of rice with a condiment, is sufficient and valid.