Apostolic Tradition 29

1Let no one at the paschal season eat before the offering is made, otherwise he shall not be credited with the fast. But if any woman is with child, or if anyone is sick and cannot fast for two days, let such a one, on account of his need, [at least] fast on Saturday, contenting himself with bread and water. But if anyone on a voyage or for any other necessary cause should not know the day, when he has learned the truth he shall postpone his fast until after Pentecost. For the ancient type has passed away, and so the [postponed] fast [of Numbers 9. 11] in the second month has ceased, and each one ought to fast in accord with his knowledge of the truth.