Sunan an Nasai
892
Daif Isnaad+2

It was narrated from Abu Ubaidah that:Abdullah saw a man who was praying with his feet together. He said: "He is going against the Sunnah; if he shifted his weight from one to the other that would be better

Daif IsnaadAbu Ghuddah
Daif IsnaadAl-Albani