Agency in buying: Abu Hanifah said he is liable if he sells without his instruction

Sayyiduna Abu Mas'ud (may Allah be pleased with him) says that the Prophet (peace and blessings be upon him) said: "A prayer in which a man does not (fully) straighten his back in its bowing and prostration does not suffice."

Ali bin Yahya bin Khallad narrates from his father, from his uncle, who had taken part in Badr, that he said: We were sitting with the Prophet (peace and blessings be upon him) when a man came in to pray. He offered a light (that is, hurried) prayer, completing neither the bowing nor the prostration. He (peace and blessings be upon him) was watching him, and the man did not realize it. So he prayed (in this way), then came and greeted the Prophet (peace and blessings be upon him) with salam. He (peace and blessings be upon him) returned the greeting and said: "Repeat (the prayer), for you have not prayed." The man did this three times. Each time he (peace and blessings be upon him) would say: "Repeat (the prayer), for you have not prayed."

It is reported about Sayyiduna al-Miswar bin Makhramah (may Allah be pleased with him) that he saw a man who was not completing his bowing and prostration. So he said to him: "Pray again!" The man refused, but he did not leave him until he had repeated it. It is mentioned that the view of (Imam) Abu Hanifah is: This prayer will suffice him, but he has done wrong.