Sahih Muslim Book 4, Hadith Number 1357.

Chapter : Desirability of observing the morning prayer at earlier hour and that is the time when there is darkness before dawn and the exposition about the length of recitation in it.

‘Abu’l-‘Aliyat al-Bara reported: Ibn Ziyad delayed the prayer. ‘Abdullah b. Samit came to me and I placed a chair for him and he sat in it and I made a mention of whit Ibn Ziyad had done. He bit hit lips (as a sign of extreme anger and annoyance) and struck at my thigh and said: I asked Abu Dharr as you have asked me, and he struck my thigh just as I have struck your thigh, and said: I asked the Messenger of Allah (may peace be upon him) as you have asked me and he struck my thigh just as I have struck your thigh, and he (the Holy Prophet) said: Observe prayer at its prescribed time, and if you can say prayer along with them. do so, and do not say. “I have observed prayer and so I shall not pray.”