Musnad Ahmad 658:148

'Abd al-Razzaq narrated to us, Sufyan informed us, from Mansur and al-A'mash, from Talha, from 'Abd al-Rahman ibn Awsajah al-Nahmi, from al-Bara' ibn 'Azib, who said: The Prophet, peace and blessings of Allah be upon him, said: "Indeed, Allah and His angels send blessings upon the first rows. And beautify the Quran with your voices. And whoever grants a gift of milk, or a gift of silver, or guides someone along a path, it is like the freeing of a slave."