Bulugh al-Maram 64
Narrated ‘Umar (rad), in a Mawquf (untraceable) and Anas in a Marfu (traceable) Hadith:
“If one of you performs ablution and puts on his two leather socks, let him perform Mash (wipe) over them and pray in them and he may not take them off he so wishes except after ejaculation or sexual impurity. [Reported by Ad-Daraqutni and Al-Hakim and graded Sahih (sound) by him].
وَعَنْ عُمَرَ ‏-مَوْقُوفًا‏- و]عَنْ] أَنَسٍ ‏-مَرْفُوعًا‏-: { إِذَا تَوَضَّأَ أَحَدُكُمْ وَلَبِسَ خُفَّيْهِ فَلْيَمْسَحْ عَلَيْهِمَا, وَلْيُصَلِّ فِيهِمَا, وَلَا يَخْلَعْهُمَا إِنْ شَاءَ إِلَّا مِنْ جَنَابَةٍ" }  أَخْرَجَهُ اَلدَّارَقُطْنِيُّ, وَالْحَاكِمُ وَصَحَّحَه ُ  1‏ .‏‏1 ‏- انظر الدارقطني (103 ‏- 204)‏، والحاكم (181)‏ .‏