divine command

{ It is He who made the earth tame1 for you - so walk among its slopes and eat of His provision }

{ disperse within the land and seek from the bounty of Allāh }

{ And marry the unmarried among you and the righteous among your male slaves and female slaves. If they should be poor, Allāh will enrich them from His bounty, and Allāh is all-Encompassing and Knowing. }