al-Zuhri ابن شهاب الزهري‎, محمد بن مسلم · The Chapters on Expiation

"If anyone of you insists on fulfilling what he swore to (after learning that it is wrong) then it is more sinful before Allah than (breaking the oath for which) the expiation that has been enjoined upon him."

'When anyone of you swears an oath, let him not say: 'What Allah wills and what you will.' Rather let him say: 'What Allah wills and then what you will.'

"There is no vow to commit disobedience, and the expiation (for such a vow) is the expiation for breaking an oath."

Messenger of Allah (ﷺ) passed by a man in Makkah who was standing in the sun. He said: "What is this?" They said: "He vowed to fast and not to seek shade until night comes, and not to speak, and to remain standing." He said: "Let him speak and seek shade and let him sit down, but let him complete his fast."Another chain from Ibn 'Abbas, from the Prophet (ﷺ), with similar wording. expiation for breaking an oath."