Mujahid reported,
"The way" means the prescribed punishment. Sufyan said, "so harm them both" 
refers to unmarried persons, and "confine them to their houses" refers to those who have been previously married.
Abu Dawud 4414
Daifحدثنا أحمد بن محمد بن ثابت حدثنا موسى يعني ابن مسعود عن شبل عن ابن أبي نجيح
عن مجاهد قال
السبيل الحد قال سفيان {فآذوهما} البكران {فأمسكوهن في البيوت} الثيبات
أبو داود 4414ضعيف
Contents
Reference
Commentary
Ayat
Collection
Sunan Abu Dawud
Book
Legal punishments
Chapter
Stoning
Numbering
Darussalam 4414