"Have We not made the earth a receptacle?" It contains them, meaning: it gathers them, and "kaft" is gathering and collecting.
﴿ألم نجْعَل الأَرْض كفاتا﴾ تَكْفِتُهُمْ، أَيْ: تَضُمُّهُمْ، والكفتُ: الضمُّ وَالْجمع
