Ishaq bin Ibrahim (may Allah have mercy on him) said about the hadith of Shaddad bin Aws (may Allah be pleased with him): This is a sahih (authentic) chain by which the proof is established, and this hadith is sahih through several chains, and we hold it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصيام / 8295