It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "The example of my Ummah is like that of rain: it is not known whether its first part is better or its last."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13662