Among its evidences is the Almighty’s saying: “O you who believe, when the call is proclaimed for prayer on Friday, hasten to the remembrance of Allah and leave off trading.” ⦗Al-Jumuʿah 62:9⦘.

Fourteenth Maxim: “Whoever seeks to hasten something before its appointed time is punished by being deprived of it.”
Meaning: Anyone who employs impermissible means, in impatience, to obtain a right that will eventually be his, finds the Law treating him with the opposite of his intention; he is divested of that benefit as a penalty for his act and his haste.
For instance, if an heir kills the person from whom he stands to inherit in order to accelerate the estate’s transfer, he is barred from the inheritance, whether the killing was suspected to be deliberate or not.
Ibn Rajab phrased the maxim thus: “Whoever uses a cause that confers ownership or licitness, or lifts an obligation, in a forbidden manner, that cause is nullified; its existence is deemed as non-existent and none of its legal effects ensue.”
Status of the maxim: It belongs to siyāsa sharʿiyya (Islamic public policy) and to the doctrine of blocking the means, as in disqualifying an heir who kills his benefactor, even if the killing was accidental.

Fifteenth Maxim: “What is established by the Sharīʿah takes precedence over what is established by a condition.”
Evidence and foundation: The Prophet ﷺ said, “Any stipulation that is not in the Book of Allah is void.” ⦗Agreed upon⦘.
“The Book of Allah” here means the rulings ordained by Allah. Therefore, anything that contradicts the fundamentals of the Sharīʿah as laid down in the Qur’an and the Sunnah renders the contract or the stipulation invalid; “the Book of Allah” is not limited to the physical Qur’an but encompasses all that Allah has prescribed in His law.
Accordingly, if a stipulation is found to conflict with the purposes of the Sharīʿah to the extent that the lawful objective of the contract is frustrated—should the matter involve contracts—then: the entire contract is void if the stipulation negates one of its essential pillars or clashes with its primary purpose. If, however, the stipulation does not negate an essential pillar, the contract remains valid and only the stipulation itself is void.