Ata, or someone else, said: The messenger of Ibn Safwan came to Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) while he was busy tending to Zamzam. He invited him and his students, so he sent his students off and excused himself, saying: "If he does not accept my excuse, I will come too."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14541