Acts 10:10-12

‘And he became hungry, and desired to eat. But while they made ready, he fell into a trance, and he sees the heaven opened, and a certain container descending, as it were like a great sheet, let down by four corners on the earth, in which were all manner of fourfooted beasts and creeping things of the earth and birds of the heaven.'

And feeling hungry he called for something to eat. This hunger may have been the result of the time he spent in prayer, and may therefore point to how long he had been praying. But while the meal was being prepared he fell into a trance, and saw what would appear to him as a nightmare. He saw a great sheet being let down from heaven filled with ‘unclean' things. This included fourfooted beasts, such as pigs, conies and camels (it was a vision), together with different kinds of birds and many creeping things (all of which, apart from locusts, would be unclean). There may have been clean animals among them (opinion is divided), but as a good Jew he must have been horrified, and would probably shudder. His heart would draw back in repulsion.