The Messenger of Allah ﷺ happened to pass by (the house) of a man amongst the Ansar, and he sent for him. He came out and water was trickling down from his head. Upon this he (the Holy Prophet) said: Perhaps we put you to haste. He said: Yes. Messenger of Allah. He (the Holy Prophet) said: When you made haste or semen is not emitted, bathing is not obligatory for you, but ablution is binding. Ibn Bashshir has narrated it with a minor alteration.
أَنَّ رَسُولَ اللَّهِ ﷺ مَرَّ عَلَى رَجُلٍ مِنَ الأَنْصَارِ فَأَرْسَلَ إِلَيْهِ فَخَرَجَ وَرَأْسُهُ يَقْطُرُ فَقَالَ لَعَلَّنَا أَعْجَلْنَاكَ قَالَ نَعَمْ يَا رَسُولَ اللَّهِ قَالَ إِذَا أُعْجِلْتَ أَوْ أَقْحَطْتَ فَلاَ غُسْلَ عَلَيْكَ وَعَلَيْكَ الْوُضُوءُ وَقَالَ ابْنُ بَشَّارٍ إِذَا أُعْجِلْتَ أَوْ أُقْحِطْتَ