Al-Matalib al-'Aliyah 121 — Things that nullify wudu

It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that he said (explaining the word 'touching' in the saying of Allah Almighty: "or you have touched women" [Surah al-Nisa: 43]): "Touching (lams) means what is short of intercourse (that is, contact with the hand and the like)."
This report (athar) is sahih (authentic), and Imam Ibn Abi Shaybah narrated it in his al-Musannaf.