If he says, “By Allah, I shall perform Hajj today,” on the fourteenth night of Jumada al-Ula, then goes to visit a friend and the sun sets, he has not broken his oath, because his words contain something that prevents them from being understood according to the legal meaning—namely, his saying, “today.”
But if he says, “By Allah, I shall perform Hajj,” without qualification, then goes to visit a friend and says, “This is Hajj: linguistically, Hajj means intending, and I intended,” we say to him: This is not possible. For when the term Hajj is used without qualification—so long as you have no particular intention and there is no contextual indication—it is understood according to its legal meaning. In this case, he has broken his oath, because he did not perform Hajj. Thus, when a word has a legal meaning and a linguistic meaning, it is understood according to its legal meaning. This is why the author says:
“An unqualified expression is construed according to the valid legal designation. Thus, if a person swears that he will neither sell nor marry, then enters into an invalid contract, he has not broken his oath, …”
“An unqualified expression is construed according to the valid legal designation. Thus, if a person swears that he will neither sell nor marry, then enters into an invalid contract, he has not broken his oath.” An unqualified term is understood according to its valid legal meaning, because once the legal meaning became widespread among Muslims, it came to resemble customary usage. For example, wudu linguistically means cleanliness, whereas legally it is washing the four limbs in a prescribed manner as an act of worship to Allah, may He be glorified and exalted. Thus, if someone says, “By Allah, I shall not perform wudu,” then goes to the bathhouse and cleans his entire body, he has not performed wudu in the legal sense and has therefore not broken his oath.
Another example: A man says, “By Allah, I shall not pray before noon,” then supplicates. If he is told, “You have broken your oath, because prayer linguistically means supplication,” we say: “No, he has not broken his oath,”