The article analyzes the obligation to refrain from work, based on the Holy Bible, the canonical tradition, the past and current legislation containing documents produced by ecumenical councils, popes, the various commissions of the Holy See, and also opinions of experts in moral theology and canon law. The first chapter describes the origin and development of this obligation, beginning with the third commandment of the Decalogue and the conduct of early Christians. It should be noted that the first relevant civil law was introduced by Constantine on 1 March 321 AD and was subsequently received by church authorities. Both councils and popes reminded Christians of the importance of refraining from work on Sundays and feasts of obligation. The second chapter analyzes the legislation of the previous Code in this field. Can. 1248 CIC/17 was very precise because it enumerated activities which one should avoid. Although this way of presenting the obligation was clear, it lost its theological and ecclesial dimension. The third chapter examines the current legislation concerning the obligation, starting with the Second Vatican Council and analyzing the documents of the Pontifical Commission for the Revision of the Code in order to interpret can. 1247 CIC/83. The chapter also takes into consideration the various documents of the Holy See issued after the promulgation of the current Code.