This is the primary purpose of man - to love God; it is why we are here. It is why there is anything at all. The second purpose is to love our neighbor as ourself
Which apparently can include slavery and infanticide. Awkward!
Morality is not about convention. It is objective because it is founded on actions that promote the flourishing of others. 'Godly' morality is arbitrary. It is based on divine whims and can include actions that are morally repugnant to all reasonable humans.