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.