عَنِ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ كَانَ يَخْرُجُ فَيُهْرِيقُ الْمَاءَ فَيَتَمَسَّحُ فَأَقُولُ: إِنَّ الْمَاءَ مِنْكَ قَرِيبٌ فَيَقُولُ: ((وَمَا أَدْرِي لَعَلِّي لَا أَبْلُغُهُ))
Sayyiduna Abdullah bin Abbas (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) used to go out and perform tayammum after urinating. When I would say that water is near you, he (peace and blessings be upon him) would say: I do not know, perhaps I may not be able to reach there.