A direct imperative is built with reference to the imperfect stem and jussive formation. A prohibition uses prohibitive lā with a jussive imperfect. Many hollow verbs lose their long medial vowel in these environments.
PerfectImperativeProhibition
أَقَامَأَقِمْلَا تُقِمْ
أَطَارَأَطِرْلَا تُطِرْ
اِسْتَعَانَاِسْتَعِنْلَا تَسْتَعِنْ
اِسْتَعَارَاِسْتَعِرْلَا تَسْتَعِرْ
اِجْتَابَاِجْتَبْلَا تَجْتَبْ
اِخْتَارَاِخْتَرْلَا تَخْتَرْ
اِنْقَادَاِنْقَدْلَا تَنْقَدْ
اِنْقَاضَاِنْقَضْلَا تَنْقَضْ
Weak-vowel contraction does not erase the characteristic additional letters of the derived form. Each command therefore retains its Form-IV, X, VIII or VII identity.