An-Nisāʾ: 81
"And they say, 'Obedience'..."
"And they say..."
When you command them to do something.
"...Obedience..."
In the nominative case (rafʿ), meaning: "Our affair and our state is obedience." It is also permissible to read it in the accusative case (naṣb), meaning: "We obey you with obedience." This is similar to the saying of one who is compliant: "Hearing and obedience" (samʿan wa-ṭāʿatan). Sibawayh mentions that he heard some reliable Arabs, when asked "How are you?", reply: "Praise to God and laudation of Him" (ḥamdun lillāh wa-thanāʾun ʿalayh), as if they said: "My affair and my state is the praise of God." If one were to use the accusative (ḥamdan wa-thanāʾan), it would be based on the verb (i.e., "I praise God"), whereas the nominative indicates the stability and permanence of that obedience.
"...a party of them..."
Meaning: A group has plotted and devised.
"...other than what you say..."
Meaning: Contrary to what you said and commanded, or contrary to what they themselves said and guaranteed of obedience; for they nullified the response, not the acceptance, and the disobedience, not the obedience.
They are hypocritical in what they say and manifest. "Plotting" (tabyīt) is derived either from "spending the night" (baytūta), because it refers to executing and planning a matter at night—it is said, "This is a matter plotted by night"—or it is derived from "verses of poetry" (abyāt al-shiʿr), because a poet plans and arranges them.
"And God writes down what they plot..."
He records it in the scrolls of their deeds and will recompense them for it, by way of a threat. Or, He writes it among the things revealed to you, so He informs you of their secrets, that they might not think their concealment will avail them anything.
"So turn away from them..."
Do not occupy your soul with taking vengeance upon them.
"...and rely upon God..."
Regarding their affair, for God will suffice you against their harm and will take vengeance for you against them when the affair of Islam grows strong and its supporters become mighty.
It has been recited as bayyata ṭāʾifatun (with assimilation), using the masculine verb because the femininity of ṭāʾifa (party) is not real, and because it carries the meaning of farīq (group) or fawj (troop).