مُوَطَّأُ مَالِكٍ
Muwatta Malik 22
The Times of Prayer
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ يَحْيَى بْنِ سَعِيدٍ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، انْصَرَفَ مِنْ صَلاَةِ الْعَصْرِ فَلَقِيَ رَجُلاً لَمْ يَشْهَدِ الْعَصْرَ فَقَالَ عُمَرُ مَا حَبَسَكَ عَنْ صَلاَةِ الْعَصْرِ فَذَكَرَ لَهُ الرَّجُلُ عُذْرًا فَقَالَ عُمَرُ طَفَّفْتَ . قَالَ يَحْيَى قَالَ مَالِكٌ وَيُقَالُ لِكُلِّ شَىْءٍ وَفَاءٌ وَتَطْفِيفٌ .
Yahya related to me from Malik from Yahya ibn Said that once Umar ibn al-Khattab left after doing the asr prayer and met a man who had not been there. Umar asked him what had kept him from the prayer and eventhough the man gave a good reason, Umar said, "You have given yourself short measure." Yahya added that Malik commented, "It is said that everything has a short measure and a full measure."
Arabic/English book reference: Book 1, Hadith 22