Aslam (may Allah have mercy on him), the freed slave of Sayyiduna Umar (may Allah be pleased with him), said: When Sayyiduna Umar (may Allah be pleased with him) came to Syria, a Christian invited him and said to Sayyiduna Umar (may Allah be pleased with him): "I would like you and your companions to come to me and honor me." This man was one of the chiefs of Syria. Sayyiduna Umar (may Allah be pleased with him) said: "We will not enter churches, because there are pictures in them."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14564