Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates: The Prophet Muhammad (peace and blessings be upon him) performed the Zuhr and Asr prayers together. He performed the Maghrib and Isha prayers together, and this was without any fear and other than during travel. Imam Malik (may Allah have mercy on him) says: I think this must have been during the rainy season.
Hadith Referenceصحیح ابن حبان / كتاب الصلاة / 1596
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح - «صحيح أبي داود» (1093): م.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط مسلم، رجاله رجال الشيخين غير أبي الزبير، فمن رجال مسلم.