Hadith: The Prophet (may Allah's peace and blessings be upon him) instructed us that during a journey we need not to take off our leather socks for up to three days and nights, except in case of major ritual impurity. In other cases such as sleeping, relieving oneself, or urinating, it is sufficient to wipe over leather socks

عن زر بن حبيش قال: أتيت صَفْوَانَ بْنَ عَسَّالٍ رضي الله عنه أسأله عن المسحِ على الخُفَّيْنِ، فقال: ما جاء بك يا زِرُّ؟ فقلت: ابتغاءَ العلمِ، فقال: إنَّ الملائكةَ تَضعُ أجنحتَها لطالبِ العلمِ رِضًى بما يطلب، فقلت: إنه قد حَكَّ في صدري المسحُ على الخُفَّيْنِ بعد الغَائِطِ والبَوْلِ، وكنتَ امرءًا من أصحابِ النبي صلى الله عليه وسلم فجئتُ أَسْأَلُكَ هل سمعتَه يذكر في ذلك شيئا؟ قال: نعم، كان يأمرُنا إذا كنا سَفْرًا -أو مُسافرين- أن لا نَنْزِعَ خِفَافَنَا ثَلاثَةَ أيَّامٍ وَلَيَالِيهِنَّ إِلَّا مِن جَنَابَةٍ، لكن مِن غَائِطٍ وبَوْلٍ ونَوْمٍ، فقلت: هل سمعتَه يذكُرُ في الهَوَى شيئا؟ قال: نَعم، كُنَّا مع رَسُولِ اللهِ صلى الله عليه وسلم في سَفَرٍ، فبينا نحن عنده إذ ناداه أعرابي بصوت له جَهُورِيٍّ: يا محمدُ، فأجابه رسولُ اللهِ صلى الله عليه وسلم نَحْوًا مِنْ صوته: «هَاؤُمُ» فقلت له: وَيْحَكَ! اغْضُضْ من صوتك فإنك عند النبي صلى الله عليه وسلم وقد نُهيتَ عن هذا! فقال: واللهِ لا أَغْضُضُ، قال الأعرابي: المرءُ يُحِبُّ القومَ ولَمَّا يَلْحَقْ بهم؟ قال النبي صلى الله عليه وسلم : «المرَّءُ مع مَن أَحَبَّ يَومَ القِيامَةِ». فما زَال يحدِّثُنا حتى ذكر بَابًا من المغْرِبِ مسيرةُ عَرضِهِ أو يَسِيرُ الرَّاكِبُ في عَرْضِهِ أربعينَ أو سبعينَ عَامًا -قال سفيانُ أحدُ الرواة: قِبَلَ الشَّامِ- خَلَقَهُ اللهُ تعالى يومَ خَلقَ السَّمَاوَاتِ والأرضَ مَفْتُوحًا للتوبةِ لا يُغْلَقُ حَتَّى تَطْلُعَ الشَّمْسُ مِنْهُ.
[حسن صحيح] - [رواه الترمذي وابن ماجه وأحمد]

Zirr ibn Hubaysh reported: I went to Safwān ibn ‘Assāl (may Allah be pleased with him) to inquire about wiping over leather socks. He asked me: "What brought you here, O Zirr?" I answered: "Pursuit of knowledge." He said: "Indeed, the angels lower their wings for the seeker of knowledge out of joy for what he seeks." I told him: "I entertain some doubts regarding wiping over leather socks after defecation or urination. Now since you are one of the Prophet’s Companions, I have come to ask you whether you heard him say anything about this!" He replied in the affirmative and said: "He instructed us that during a journey, we need not take off our leather socks for up to three days and nights, except in case of Janābah. In other cases such as sleeping, relieving oneself, or urinating, it is sufficient to wipe over leather socks." Then, I asked him: "Did you hear him say anything about love?" He replied: "Yes. While we were with the Messenger of Allah (may Allah’s peace and blessings be upon him) on a journey, a Bedouin called out in a loud voice: 'O Muhammad!' The Messenger of Allah (may Allah’s peace and blessings be upon him) replied in the same tone: 'Here I am!' I said to the Bedouin: 'Woe to you! Lower your voice, for you are in the Prophet’s presence, where you are not allowed to do so.' He said: 'By Allah! I will not lower my voice.’ Then, addressing the Prophet, he said: 'What about a person who loves some people but cannot catch up with them?' The Prophet (may Allah's peace and blessings be upon him) replied: 'A person shall be with those whom he loves on the Day of Judgment.' He kept speaking to us, and during his speech he mentioned a gate in the direction of the west, the width of which or the rider crosses its width in forty or seventy years." Sufyān, one of the narrators, said: "This gate lies in the direction of the Levant. Allah, the Almighty, created it on the day He created the heavens and the earth. It is open for repentance and will not be closed until the sun rises from that direction.
Hasan Sahih /Sound-Authentic. - [Ibn Maajah]

Explanation

Zirr ibn Hubaysh went to Safwān ibn ‘Assāl (may Allah be pleased with him) to ask about wiping over leather socks. Safwān asked him about the reason for his coming. "To seek knowledge," he replied. Thereupon, Safwān informed him that the angels stop their wings from flying and stay calm out of reverence for the seeker of knowledge and joy about his object of pursuit. Zirr said: I am confused and doubtful about wiping over leather socks after urination or defecation, as to whether this is permissible or not. Safwān clarified to him that this is permissible, since the Prophet (may Allah's peace and blessings be upon him) instructed that whenever they were on a journey, they need not take off their leather socks, except for washing after sexual impurity, in which case one should take off his footwear and the like. But when a person performs ablution after sleeping or answering the call of nature, he may wipe over his leather socks. Thereafter, Zirr ibn Hubaysh asked Safwān whether he heard the Prophet (may Allah's peace and blessings be upon him) say anything about love. Safwān replied in the affirmative and then related a story involving a loud-voiced Bedouin who came and called out loudly: O Muhammad! So, he was reprimanded for speaking loudly to the Prophet (may Allah's peace and blessings be upon him) whereas Allah, the Almighty, says: {O you who have believed, do not raise your voices above the voice of the Prophet or be loud to him in speech like the loudness of some of you to others, lest your deeds become worthless while you perceive not} [Sūrat al-Hujurāt: 2]. Bedouins, however, do not embrace etiquette and good manners, for they live away from cities and are removed from knowledge. The Prophet (may Allah's peace and blessings be upon him) replied to him in a similar tone. An example of the perfect guidance and wisdom, he would treat everyone in a manner that suits their understanding. That is why he addressed him similarly. Then, the Bedouin asked: "What about a person who loves some people but cannot catch up with them?" In other words, a person may love certain people but he lags behind in terms of good deeds. Will he be in their company or not? The Prophet (may Allah's peace and blessings be upon him) made it clear that "a person shall be with those he loves on the Day of Judgment." Zirr added: Then, the Messenger of Allah (may Allah’s peace and blessings be upon him) kept speaking to us, and during his speech he mentioned a gate in the direction of the west, the distance between its ends, or the amount of time it takes a rider to cross its width, is forty or seventy years. It lies in the direction of Syria. Allah, the Almighty, created it on the day He created the heavens and the earth. It is open for repentance and will not be closed until the sun rises from the west.