Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said that Sayyiduna Umar (may Allah be pleased with him), sitting on the pulpit, was saying: Allah Almighty sent Muhammad (peace and blessings be upon him) with the truth; Allah Almighty revealed His Book to him (peace and blessings be upon him), and in it He also revealed the verse of stoning. We recited it and we memorised it. He (peace and blessings be upon him) carried out stoning, and after him (peace and blessings be upon him) we also carried out stoning. I fear that after some time people will arise who will say, 'We do not find stoning in the Book of Allah,' and so they will go astray by abandoning an obligation revealed by Allah. Stoning is (prescribed) in the Book of Allah for every man and woman who is married (and commits adultery), when there is evidence against them, or they confess, or pregnancy occurs.
Ibn Shihab (may Allah have mercy on him) said: If a man is married but has not yet touched his wife and he commits adultery, there is no stoning for him; rather, stoning is for the one who has touched his wife. Otherwise, if he is free, he is given 100 lashes and exiled for one year.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحدود / 16909