Mishkat al-Masabih 3683
Abu Musa said:
Two of my cousins on my father’s side and I went in to see the Prophet and one of them said, “Messenger of God, put us in command of part of what God has put in your charge,” the other also saying the same. He replied, “I swear by God that I will not put in charge, of this work anyone who asks for it, or anyone who is eager for it.” In a version he said, “We will not employ in our work one who wants it.” 

(Bukhari and Muslim.)
وَعَنْ أَبِي مُوسَى قَالَ: دَخَلْتُ عَلَى النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَا وَرَجُلَانِ مِنْ بَنِي عَمِّي فَقَالَ أَحَدُهُمَا: يَا رَسُولَ اللَّهِ أَمِّرْنَا عَلَى بَعْضِ مَا وَلَّاكَ اللَّهُ وَقَالَ الْآخَرُ مِثْلَ ذَلِكَ فَقَالَ: «إِنَّا وَاللَّهِ لَا نُوَلِّي عَلَى هَذَا الْعَمَلِ أَحَدًا سَأَلَهُ وَلَا أَحَدًا حَرَصَ عَلَيْهِ» . وَفِي رِوَايَةٍ قَالَ: «لَا نَسْتَعْمِلُ عَلَى عَمَلِنَا مَنْ أَرَادَهُ»