When Sayyiduna Umar (may Allah be pleased with him) came to al-Sham, Sayyiduna Abu Ubaydah bin al-Jarrah (may Allah be pleased with him) went out to receive him and kissed his hand. Then they went off alone and began to weep. The narrator said: Tamim (may Allah have mercy on him) used to say: Kissing the hands is a sunnah.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13585