Mishkat al-Masabih 4 Prayer كتاب الصلاة 37

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا أَدْرَكَ أَحَدُكُمْ سَجْدَةً مِنْ صَلَاةِ الْعَصْرِ قَبْلَ أَنْ تَغْرُبَ الشَّمْسُ فَلْيُتِمَّ صَلَاتَهُ وَإِذَا أَدْرَكَ سَجْدَةً مِنْ صَلَاةِ الصُّبْحِ قَبْلَ أَنْ تَطْلُعَ الشَّمْسُ فَلْيُتِمَّ صَلَاتَهُ» . رَوَاهُ البُخَارِيّ

He also reported God’s Messenger as saying, “If any of you performs a sajda of the afternoon prayer before sunset, he should complete his prayer; and if he is present at a sajda of the Morning Prayer before sunrise, he should complete his prayer.” Bukhari transmitted it.