Three Questions by a Christian from Ja’far as-Sadiq

I was there I made ablutions and prayed at noon every day. One day the Christian in the monastery asked me, ‘What is this manner of praying? I have never seen anyone pray like this.’ I replied, ‘I have learned it from the (grand)son of God’s Prophet (MGB).’ The man asked, ‘Is he knowledgeable?’ I replied, ‘Yes.’ The man said, ‘Then ask him about the following three things: what eggs, fish and birds are forbidden to eat?’ I went on Hajj pilgrimage that year and went to see Aba Abdullah as-Sadiq (MGB) and told him, ‘A man has asked me three things.” He (MGB) said, “What are they?” I said, “He asked me which eggs, fish and birds are forbidden to eat?” The Imam (MGB) replied, “You should not eat any eggs whose tips are the same (the top of which you cannot distinguish from its bottom). You should not eat fish which has no scales. You should not eat any birds which do not have any gizzards” Upon my return from Mecca, I went to see the Christian man and gave him the answer. He said, “The man who has provided this answer is either a Prophet or a Trustee of a Prophet.”The compiler of the book - may God be pleased with him - said, “You can eat any of the sea birds that have gizzards or spur. You can eat birds which flap their wings when they fly. You should not eat birds which glide. Regarding birds that both glide and flap their wings when they fly, you can eat birds which flap their wings more often than they glide. However, you should not eat those which glide more often than they flap their wings.”