Barirah came to seek my help regarding her manumission (freedom). I told herself you like I would pay your price
to your masters but your Wala' (allegiance) would be for me." Her masters said, "If you like, you can
pay what remains (of the price of her manumission), (Sufyan the sub-narrator once said), or if you like
you can manumit her, but her (inheritance) Al-Wala would be for us. "When Allah's Messenger (ﷺ) came, I
spoke to him about it. He said, "Buy her and manumit her. No doubt Al-Wala' is for the manumitted."
Then Allah's Messenger (ﷺ) stood on the pulpit (or Allah's Messenger (ﷺ) ascended the pulpit as Sufyan once said),
and said, "What about some people who impose conditions which are not present in Allah's Book
(Laws)? Whoever imposes conditions which are not in Allah's Book (Laws), his conditions will be
invalid even if he imposed them a hundred times."
Sahih al-Bukhari Book 8, Hadith 104
"I came to the Messenger of Allah (ﷺ) with a group of Asharites and asked him to give us animals to ride. He said: 'By Allah, I cannot give you anything to ride, and I have nothing to give you to ride.' We stayed as long as Allah willed, then some camels were brought to him. He ordered that we be given three she-camels with fine humps. When we left, we said to one another: 'We came to the Messenger of Allah (ﷺ) to ask him for animals to ride, and he swore by Allah that he would not give us anything to ride, then he gave us something. Let us go back.' So we went to him and we said: 'O Messenger of Allah! We came to you seeking mounts, and you took an oath that you would not give us mounts, then you gave us some mounts.' He said: 'By Allah, I did not give you animals to ride, rather Allah gave you them to ride. I, by Allah, if Allah wills, do not swear and then see something better than it, but I offer expiation for what I swore about, and do that which is better.' Or he said: 'I do that which is better and offer expiation for what I swore about.'"
Sunan Ibn Majah Book 11, Hadith 18