Mishkat al-Masabih 14 Emancipation كتاب العتق 16

وَعَن الْمَلِيحِ عَنْ أَبِيهِ: أَنَّ رَجُلًا أَعْتَقَ شِقْصًا مِنْ غُلَامٍ فَذَكَرَ ذَلِكَ لِلنَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ: «لَيْسَ لِلَّهِ شَرِيكٌ» فَأَجَازَ عتقه. رَوَاهُ أَبُو دَاوُد

Abul Malih told on his father’s authority that when a man emancipated a share in a slave, and the matter was mentioned to the Prophet he said, “God has no partner,” and decided chat he should be emancipated. Abu Dawud transmitted it.