Sayyiduna Abdullah bin Amr reports this saying of the Prophet (peace and blessings be upon him): "The example of my Ummah is like rain: it is not known whether its first part is better, or its last part."
Al-Tabarani recorded it; its chain contains Abd al-Rahman bin Ziyad bin An'um, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 16710