Strict

The triliteral root ghayn lām ẓā (غ ل ظ) occurs in the Quran 13 times.

Strict covenant

(4:21) How can you take it when you have become intimate with each other, and they have taken from you a strict (Arab. غَلِيظًا, ghalīẓan) covenant?

(33:7) When We took from the prophets their covenant. From you, and from Noah, and Abraham, and Moses, and Jesus the son of Mary; We took from them a strict (Arab. غَلِيظًا, ghalīẓan) covenant.