2/231 — Keeping her in order to harm
"When you divorce women and they reach the end of their waiting period, either keep them in a fitting way or release them in a fitting way. Do not keep them in order to harm them, to transgress against them."
ضِرَارًا لِّتَعْتَدُوا۟ — root ض-ر-ر, and the pattern is Form III (mufāʿala): it conveys reciprocity or intent. That is, "so that she may be harmed, knowingly."
The verse brings intention into the ruling. The act is the same — taking back. But if the intention is different the ruling changes: what is permitted at verse 228 with in arādū iṣlāḥan (if they want to set things right) is forbidden here when done ḍirāran (in order to harm).
I record this as an observation: in the same section the same act occurs twice, and what separates them is intention alone.
وَلَا تَتَّخِذُوٓا۟ ءَايَٰتِ ٱللَّهِ هُزُوًا — "do not take God's verses in mockery." That this sentence is placed here is striking: to use a ruling in due form and turn it against its purpose is called mockery in the verse.
This is the continuation of the pattern followed in the sūra: at 2/188 doing wrong by making the law an instrument, at 2/65 going round the prohibition, at 2/42 dressing falsehood in the garment of truth. In all of them the form is preserved and the function emptied out.