Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
suyuti:1436a –

"If two (separate) authorized persons make a sale (of the same thing), then the first transaction is the one that is valid. " (Using translation from Ibn Mājah 2191)   

السيوطي:١٤٣٦a –

"إذَا باعَ المُجيزَانِ فَهُو لْلأَوَّلِ".  

[هـ] ابن ماجة عن سمرة

See similar narrations below:

Collected by Ibn Mājah
ibnmajah:2191 – al-Ḥusayn b. Abū al-Sarī al-ʿAsqalānī And Muḥammad b. Ismāʿīl > Wakīʿ > Saʿīd b. Bashīr > Qatādah > al-Ḥasan > Samurah

"If two (separate) authorized persons make a sale (of the same thing), then the first transaction is the one that is valid. "  

ابن ماجة:٢١٩١ – حَدَّثَنَا الْحُسَيْنُ بْنُ أَبِي السَّرِيِّ الْعَسْقَلاَنِيُّ وَمُحَمَّدُ بْنُ إِسْمَاعِيلَ قَالاَ حَدَّثَنَا وَكِيعٌ حَدَّثَنَا سَعِيدُ بْنُ بَشِيرٍ عَنْ قَتَادَةَ عَنِ الْحَسَنِ عَنْ سَمُرَةَ قَالَ

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا بَاعَ الْمُجِيزَانِ فَهُوَ لِلأَوَّلِ