Abu Jamrah narrates from Ibn Abbas (may Allah be pleased with them both): I asked him: Should I shorten the prayer on a journey to al-Ubullah? He said: Do you come back within the same day? I said: Yes. He said: Then do not shorten.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5400