Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: Whoever forgets something of his rites, or leaves it out, should shed blood (offer a sacrifice). Imam Malik (may Allah have mercy on him) said: I do not know whether he gave this ruling for the one who forgets or for the one who leaves it out.
The Shaykh (may Allah have mercy on him) said: Ayyub likewise reported this statement, that whoever forgets something of his rites or leaves it out should shed blood, as if he said both things. And it has been reported to us from Ata bin Abi Rabah (may Allah have mercy on him) that he said: Whoever forgets to stone one Jamrah or all the Jamarat, one sacrifice of blood will suffice him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9688