(b) If the acts impede one another, or if the legislator wishes his laws to be fulfilled at distinct times, the different obligations cannot be satisfied simultaneously. Examples: If a distracted person has received a penance to hear six Masses, he cannot hear them all at once, on account of the division of attention necessary. If the confessor told a person to hear Mass “three times,” the latter cannot satisfy by hearing three Masses at one time. 468. When a law prescribes not only what is to be done, but when it is to be done, the time must be observed. But the obligation does not always cease with the expiration of the time. (a) If the time set by the law is a limit beyond which the obligation ceases, he who has not complied within that time has no further obligation. Examples: He who did not fast on Christmas Eve, would not be obliged to fast on Christmas Day. He who did not hear Mass on Sunday, would not be obliged to hear Mass on Monday. (b) If the time set by the law is not a limit to terminate the obligation, but a date fixed in order to insist on the obligation, he who has not complied within the prescribed period, is nevertheless still obliged. Examples: He who has not made the Easter duty by Trinity Sunday, is obliged to receive Communion after Trinity. He who has not paid a debt on the day required by law, is bound to pay it after that day. 469. It depends on the intention of the lawgiver whether the time he prescribes for fulfillment is a limitation of the obligation or not. The intention of the lawgiver is known either from the words or purpose of the law, or from custom. 470. If the law declares that some duty must be performed within a determined period, allowing freedom for earlier or later performance within the period, the following points must be considered. (a) A person is not obliged to comply early, if he intends to comply before the period has ended. (b) He is obliged to comply early, if he foresees that later he will not be able to do what is required. Examples: If a person who has not made his Easter duty has the opportunity to receive Communion on Easter Sunday, and will not have another such opportunity till Christmas, he is obliged to receive on Easter Sunday. But, if he can communicate any Sunday during the Paschal time, he is not bound to do so on one of the early Sundays. If one can hear an early Mass, but not another Mass, on a holyday, one must hear the early Mass. 471. Just as one may not delay fulfillment until after the time set by law, so neither may one anticipate fulfillment before the time determined, unless the law may be considered to allow this. Examples: If a person has heard Mass on Saturday, he has no right to make this count for the following day. A rosary said before confession cannot be considered as performance of the penance, if in confession one is given the rosary to say.