مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 332
Purification
Circumstances which make ablution necessary - Section 3
وَعَن ابْن عُمَرَ أَنَّ عُمَرَ بْنَ الْخَطَّابِ رَضِيَ اللَّهُ عَنْهُ قَالَ: إِن الْقبْلَة من اللَّمْس فتوضؤوا مِنْهَا
Ibn ‘Umar reported ‘Umar b. al-Khattab as saying, “A kiss is connected with sexual intercourse, so perform ablution on that account.”
Mishkat al-Masabih, 332ضَعِيف (الألباني)