Sunan an-Nasa'i

It was narrated from Hani bin 'Abdullah bin Shikhkhir that his father said: "I was traveling and I came to the Prophet when he was eating and I was fasting. He said: “Come and eat.' I said: “I am fasting.' He said: “Do you know what Allah has waived for the traveler?' he said: “Do you know what Allah has waived for the traveler?' I said: “What has Allah waived for the traveler?' He said: “Fasting and half of the prayer””””””"