The essay is devoted to the role of promise as a moral concept, and, more narrowly, the relationship of promise and offer in contract law. First, it considers the difference between "ordinary" promises and promises having a legal effect. Secondly, the analysis explores to what extent does promise generate obligation. Thereafter, the essay attempts to point to the concept of obligation that provides the best way to establish the moral force of contract. It reaches the conclusion that the relationship between promise as a moral category and facts treated as promise in law is almost accidental. Law is at least indifferent to factors that give rise to moral obligation based upon a promise. However, law (emancipated from the dictates of morals) ...