Abu Bakr thought that he interpreted the dream well and when the Prophet salla Allahu alaihi wa sallam told him that he had some right and others wrong. He swore that the Prophet salla Allahu alaihi wa sallam should tell him. the Prophet told him not to swear as he is not obliged to do so.

I read this Hadith and i did not understand the last part why did the Prophet Mohammad PBUH say (Do not swear). kindly help. Narrated Ibn ‘Abbas: A man came to Allah’s Apostle and said, “I saw in a dream, a cloud having shade. Butter and honey were dropping from it and I saw the people gathering it in their hands, some gathering much and some a little. And behold, there was a rope extending from the earth to the sky, and I saw that you (the Prophet) held it and went up, and then another man held it and went up and (after that) another (third) held it and went up, and then after another (fourth) man held it, but it broke and then got connected again.” Abu Bakr said, “O Allah’s Apostle! Let my father be sacrificed for you! Allow me to interpret this dream.” The Prophet said to him, “Interpret it.” Abu Bakr said, “The cloud with shade symbolizes Islam, and the butter and honey dropping from it, symbolizes the Quran, its sweetness dropping and some people learning much of the Qur’an and some a little. The rope which is extended from the sky to the earth is the Truth which you (the Prophet) are following. You follow it and Allah will raise you high with it, and then another man will follow it and will rise up with it and another person will follow it and then another man will follow it but it will break and then it will be connected for him and he will rise up with it. O Allah’s Apostle! Let my father be sacrificed for you! Am I right or wrong?” The Prophet replied, “You are right in some of it and wrong in some.” Abu Bakr said, “O Allah’s Prophet! By Allah, you must tell me in what I was wrong.” The Prophet said, “Do not swear.”