Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates that the Messenger of Allah (peace and blessings be upon him) said: "O people of Makkah, do not shorten the prayer on a journey of less than four burd, i.e. 48 miles, (the distance) from Makkah to Usfan."
This hadith is da'if (weak): Isma'il bin Ayyash is not used as evidence, and Abd al-Wahhab bin Mujahid is very weak. The correct view is that this is the statement of Ibn Abbas (himself), as mentioned earlier.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5404