Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) narrates from the Prophet (peace and blessings be upon him): "As long as the Abyssinians leave you alone, leave them alone, for no one will take out the treasures of the Ka'bah except the man with two thin shins from Abyssinia."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18598