Jabir reported Allah's Messenger (ﷺ) as saying
Sacrifice only a grown-up animal, unless it is difficult for you, in which case sacrifice a ram (of even less than a year, but more than six months' age).
Jabir b. 'Abdullah reported
Allah's Messenger (ﷺ) led us in the 'Id prayer in Medina on the Day of Sacrifice. Some persons slaughtered their animals ahead of him under the impression that Allah's Apostle (ﷺ) had-already offered sacrifice. Thereupon Allah's Apostle (ﷺ) said: Those who had slaughtered their animals ahead of him should slaughter the other ones in their stead. And they should not sacrifice the animal before Allah's Messenger (ﷺ) had sacrificed (his animal)
Uqba b. 'Amir reported that Allah's Messenger (ﷺ) gave the gifts of goats to be distributed amongst his Companions. They sacrificed them, but a lamb of one year of age was left. (Someone) made a mention of that to the Messenger of Allah (ﷺ), whereupon he said
You sacrifice it.
Amir al-Juhani reported
Allah's Messenger (ﷺ) distributed sacrificial animals (amongst us for sacrificing them on 'Id al-Adha). So we sacrificed them. There fell to my lot a lamb of less than one year I said: Allah's Messenger, there has fallen to my lot a lamb (Jadha'a), whereupon he said: Sacrifice that.
This hadith has been transmitted on the authority of 'Uqba b. 'Amir al-Juhan with a slight change of wording.