It is narrated from Ibn Abbas (may Allah be pleased with them both) that he said: "The one who takes an oath of *ila* is he who swears never to approach his wife forever."
Hadith Referenceمسند الإمام الشافعي / كتاب عشرة النساء والإيلاء والخلع / 1223
Hadith Takhrijصحيح اخرجه البيهقي: 380/2 - وفي المعرفة السنن والآثار له (4522) - وعبد الرزاق (11608)۔