This verse ﴾جَعَلَ لَكُمْ الأَرْضَ فِرَاشاً﴿ “made for you the earth as a bed [spread out]” means that Allah U had prepared for human beings from before they were born the means of their living, comfort and happiness. Thus, He made the Earth wide like a bed and manageable for human beings, to enable them to live on it.
Al-Firash: It is the place that a human being rests on, like a bed
Al-Mahd: It is the place that a child rests in.
This means that He prepared all the components which would make the lives of human beings on this Earth possible. He makes it spherical, rotating on its own axis and also revolving around the sun. He puts the right amount of gases in the air. He put rivers on Earth and an ozone layer surrounding it. In short, He made the Earth and everything on it suitable for the dwelling of human beings and to provide them comfort.