Musannaf Ibn Abi Shaybah

Hazrat Habib bin Shaheed says that Muhammad was asked about the words of Tashahhud, so he replied that the words of Tashahhud are: All verbal worship, physical worship, and financial worship are for Allah. Then he said that Hazrat Ibn Abbas (may Allah be pleased with them both) used to add "al-barakat" (the blessings) to them.