From Sahih Muslim (Hadith 3384):
Abu Hurairah (Allah be pleased with him) reported it directly from Allah's Apostle (ﷺ) that he said:Do not undertake a journey to visit any Mosque, but three: this Mosque of mine, the Mosque of al-Haram and the Mosque of Aqsa (Bait al-Maqdis)
Reference: Muslim 3384