Love’s not time’s fool, though rosy lips and cheeks within his bending sickle’s compass come; love alters not with his brief hours and weeks, but bears it out even to the edge of doom. in sonnet 116 by william shakespeare, what text structure of a sonnet do these lines illustrate

I would say these lines illustrate a quatrain.
A quatrain is a stanza consisting of four lines, as is the case here. Shakespeare's sonnets have a specific structure - the first twelve lines are divided into three quatrains (4*3 =12); the final two lines are called a couplet, and the message of the entire sonnet can be found in those two final lines. 

Ii go icing if icing. i gig. i gig oh o hbu. igbo i gxtieuudzurxircgojb k no nfufuzitd