According to a reliable chain of narrators Imam Ja‘far as-Sadiq said that Salih was in occultation for a long time. He was middle-aged at that time. He had a handsome body and a flourishing beard and was of medium stature. When he reappeared, the people failed to recognize him. Prior to his return, there were three groups among the people. One group used to reject and said that Salih was no more alive and that he could never return. The second group was in doubt. The third group was sure that he would come back. When Salih returned, he first went to the group that was in doubt and said, “I am Salih.” They rejected him saying that he did not resemble him. Then Salih came to those were his deniers. They also did not accept him and expressed extreme dislike for him. Finally, he came to the group steadfast in faith and said, “I am Salih.”
“Show us a sign to remove all doubts,” they demanded. “We know that Allah is the creator and He can change the appearance of whomsoever He likes. We are aware of the special characteristics of Salih. We have also found in the books that he will return.” “I am the one who had brought for you the she-camel,” said Salih. “You speak the truth,” accepted the people, “We have read this in our books. Tell us the sign of the she-camel.” “One day is allotted for the she-camel to drink water and the next for you.” They said, “We believe in Allah and in all things that you have brought from Him.” The arrogant group who were harboring doubts said, “We do not accept what you believe.” The narrator says that I asked, “O son of the Messenger! Was there no Scholar among them?” Imam said, “Allah is more just that he will leave the earth without a scholar. When Salih reappeared all the scholars came to him. And in this Ummah the example of ‘Ali and the Awaited al-Qa’im (Peace of Allah be on both) is like that of Salih – Both of them will reappear towards the end of time and at that time also people will divide into three groups. Some of them will accept them and others reject them.
Reference: Hayat Al-Qulub, Vol. 1, Stories of the Prophets