Musannaf Ibn Abi Shayba 21:163

Yazid ibn Harun narrated to us, [he said] Muhammad ibn Abd al-Rahman ibn al-Khayr informed us, from Safwan ibn Sulaym, from Ata ibn Yasar, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever says when he enters the evening, 'I am pleased with Allah as a Lord, with Islam as a religion, and with Muhammad as a Messenger,' has attained the reality of faith."