The Messenger of Allah ﷺ said to me: 'Abdul al-Rahman b. Samurah, do not ask for the position of commander, for if you are given it after asking you will be left to discharge it yourself, but if you are given it without asking you will be helped to discharge it.  

لِيَ النَّبِيُّ ﷺ يَا عَبْدَ الرَّحْمَنِ بْنَ سَمُرَةَ لاَ تَسْأَلِ الإِمَارَةَ فَإِنَّكَ إِذَا أُعْطِيتَهَا عَنْ مَسْأَلَةٍ وُكِلْتَ فِيهَا إِلَى نَفْسِكَ وَإِنْ أُعْطِيتَهَا عَنْ غَيْرِ مَسْأَلَةٍ أُعِنْتَ عَلَيْهَا  

I went along with two men to see the Prophet ﷺ. One of them recited tashahhud and said: We have come to you so that you may employ us for your work. The other also said the same thing. He (the Prophet) replied: The most faithless of you in our eyes is the one who asked for it (responsible post). Abu Musa then apologized to the Prophet ﷺ and said: I did not know why they came to you. He did not employ them for anything until he died.  

انْطَلَقْتُ مَعَ رَجُلَيْنِ إِلَى النَّبِيِّ ﷺ فَتَشَهَّدَ أَحَدُهُمَا ثُمَّ قَالَ جِئْنَا لِتَسْتَعِينَ بِنَا عَلَى عَمَلِكَ وَقَالَ الآخَرُ مِثْلَ قَوْلِ صَاحِبِهِ فَقَالَ إِنَّ أَخْوَنَكُمْ عِنْدَنَا مَنْ طَلَبَهُ فَاعْتَذَرَ أَبُو مُوسَى إِلَى النَّبِيِّ ﷺ وَقَالَ لَمْ أَعْلَمْ لِمَا جَاءَا لَهُ فَلَمْ يَسْتَعِنْ بِهِمَا عَلَى شَىْءٍ حَتَّى مَاتَ