Sahih (Sahih al-Bukhari)
وَقَالَ لَنَا أَبُو الْوَلِيدِ حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ ثَابِتٍ، عَنْ أَنَسٍ، عَنْ أُبَىٍّ، قَالَ كُنَّا نَرَى هَذَا مِنَ الْقُرْآنِ حَتَّى نَزَلَتْ {أَلْهَاكُمُ التَّكَاثُرُ}
Ubayy said (referring to the hadith above), "We considered this as a saying from the Qur'an till the Surah (beginning with):"The mutual rivalry (for piling up of worldly things) diverts you' (102:1) was revealed