‘He did still another exploit,’ said Fiachu mac Fir Fhebe. ‘Cathbad the druid was with his son Conchobar mac Nessa. There were with him a hundred active men learning the druid’s art — that was the number that Cathbad used to instruct. One of his pupils asked him for what that day would be of good omen. Cathbad said that if a warrior took up arms on that day, his name for deeds of valour would be known throughout Ireland and his fame would last for ever. Cú Chulainn heard this. He went to Conchobar to ask for arms. Conchobar asked: ‘Who prophesied good fortune for you?’ ‘Master Cathbad,’ said Cú Chulainn. ‘We know him indeed,’ said Conchobar. He gave him a spear and a shield. Cú Chulainn brandished them in the middle of the hall so that not one was left unbroken of the fifteen spare sets of weapons which were kept in Conchobar’s household to replace broken weapons or to provide for the taking up of arms by someone. Finally Conchobar’s own arms were given to him. They withstood him, and he brandished them and blessed the king whose arms they were, saying: ‘Happy the people and race over whom reigns the owner of these arms.’
‘Then Cathbad came to them and asked: ‘Is the boy taking up arms?’ ‘Yes,’ said Conchobar.
‘That is not lucky for the son of his mother,’ said he. ‘Why, was it not you who instructed him?’ ‘It was not I indeed,’ said Cathbad. ‘What use is it for you to deceive me so, you sprite?’ said Conchobar to Cú Chulainn. ‘O king of the Fían, it is no deceit,’ said Cú Chulainn. ‘He prophesied good fortune for his pupils this morning and I heard him from where I was on the south side of Emain, and then I came to you.’ ‘It is indeed a day of good omen,’ said Cathbad. ‘It is certain that he who takes up arms today will be famous and renowned, but he will, however, be short-lived.’ ‘A mighty thing!’ said Cú Chulainn. ‘Provided I be famous, I am content to be only one day on earth.’
– Táin Bó Cúalnge.