Al-Matalib al-'Aliyah 3720 — Surah al-Hujurat

It is narrated from Mughirah (may Allah have mercy on him) that he said: I came to Ibrahim al-Nakha'i and said that a man called Sa'd al-Anazi had disputed with me (over a scholarly matter). Ibrahim al-Nakha'i said (correcting him): "He is not al-Anazi; rather he is al-Zubaydi." (Mughirah said that) this man had taken the position, concerning this statement of Allah Almighty: "The Bedouins say, 'We have believed.' Say: You have not believed; but say, 'We have submitted'" [Surah al-Hujurat: 14], that "what is meant by this (aslamna) is merely outward submission and laying down of arms, being overpowered, in order to save one's life (al-istislam)." At this Ibrahim al-Nakha'i said (refuting it): "No, rather it means entering the religion of Islam."
Musnad Ishaq bin Rahwayh: 3734; its chain is sahih (authentic), and this is a weighty exegetical statement of Imam Ibrahim al-Nakha'i.