Are permissible matters punishable by God, and what is the difference between obligatory, recommended, and permissible matters?

Obligatory acts are those for which the doer is rewarded and the ترك (one who abstains) is punished, such as prayer and zakat. As for recommended acts, the doer is rewarded, but the one who abstains is not punished, like supererogatory prayers. Permissible acts have no reward for doing them and no punishment for abstaining from them, such as walking and riding; these are matters in which there is no harm in doing or not doing them.