Well, it's not latent, but no one ever point it out.
Read the word "last", you may find out that these two words are connected in meaning, the
concubine also means last in its two forms.
Last 1: The concubine is the last woman he has, means?
last 2: He has enough provisions to last his concubine a whole life, his purpose is also to
have her to last his lineage.
But there is another explanation for it in different direction, this tells us the character
of sphere of words.
