Devibhagavatapurana 5.33.32

5.33.32

jagmaturmātumagrasthaṃ liṅgamadbhutadarśanam |
pātālamagamadviṣṇurbrahmāpyākāśameva ca ||

The Risi said:-- O King! Hearing thus the divine word, both of them became ready and began energetically to measure the length of the wonderful Lingam that stood in front of them. Visnu went down to Pâtâla and Brahmâ went up to Âkâs’a to measure the Lingam and thus to ascertain their superiority. Going down some distance Visnu got tired and doing his best, when he could not find out the end of the Lingam, he returned and remained at the desired meeting place. On the other hand, Brahmâ was ascending to the skies when he got one Ketakî flower dropping from the head of the Lingam. He became over glad and returned also to the desired meeting place. Brahmâ became very much elated with vanity and when he returned, he at once showed that flower to Visnu and spoke thus the false words:-- “O Visnu! This Ketakî flower has been obtained from the head of the Lingam. I have brought this to you simply that you would recognise it and be convinced in your heart.” Hearing these words of Brahmâ, Visnu saw the Ketakî flower and said:-- “O Brahmâ! Who is your witness in this matter? He whose words are true, who is equal to all, who is intelligent, pure, and always of good conduct, he can be the witness in such matters of dispute.”