Al-Rabi' (may Allah have mercy on him) informed us: I said to Imam al-Shafi'i (may Allah have mercy on him): Our companion has said: I found people who reject what some people said from Umar (may Allah be pleased with him). Imam al-Shafi'i (may Allah have mercy on him) said: We have seen someone who rejects the whole of Umar's (may Allah be pleased with him) judgement concerning the wife of the missing husband, and he says: This does not resemble the judgements of Umar (may Allah be pleased with him). When trustworthy narrators have reported it from Umar (may Allah be pleased with him), they are not to be accused. In the same way the proof is against you. And how can it be permissible that trustworthy narrators narrate a single hadith from Umar (may Allah be pleased with him), and we take part of it and leave part of it?
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15573