Salim narrates from his father (may Allah be pleased with them both) that Sayyiduna Umar (may Allah be pleased with him) asked the Prophet (peace and blessings be upon him) for permission to perform Umrah, and the Prophet (peace and blessings be upon him) said: "Include us in your supplications, and do not forget us."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10314