Abu Huraira reported God’s Messenger as saying, “If anyone performs a <i>rak'a</i> of the Morning Prayer before sunrise, he has observed the Morning Prayer; and if anyone performs a <i>rak'a</i> of the afternoon prayer before sunset, he has observed the afternoon prayer.” (Bukhari and Muslim.)

وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ أَدْرَكَ رَكْعَةً مِنَ الصُّبْحِ قَبْلَ أَنْ تَطْلُعَ الشَّمْسُ فَقَدْ أَدْرَكَ الصُّبْحَ. وَمَنْ أَدْرَكَ رَكْعَةً مِنَ الْعَصْرِ قَبْلَ أَنْ تغرب الشَّمْس فقد أدْرك الْعَصْر»