Ali bin Rabi'ah (may Allah have mercy on him) narrates: We set out with Sayyiduna Ali (may Allah be pleased with him) and we shortened (the prayer) while we could (still) see the houses. Then when we returned, we (again) shortened it, even though we could see our houses. We spoke to Sayyiduna Ali (may Allah be pleased with him) (about this), and he said: "We will keep shortening until we enter it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5449