[Machine] "The power of the guardian is permissible in everything except in the act of buying, and when someone sells, it is not considered valid." This is the opinion of Yahya ibn Hamza.
«أَمْرُ الْوَصِيِّ جَائِزٌ فِي كُلِّ شَيْءٍ إِلَّا فِي الِابْتِيَاعِ وَإِذَا بَاعَ بَيْعًا لَمْ يُقِلْ» وَهُوَ رَأْيُ يَحْيَى بْنِ حَمْزَةَ