This little poem comes from Disticha de Educatione of Urbano Appendini, published in 1834; you can see the whole book at Google Books.
Quando Peccas Tu
Si quis peccantem te corrigit, illius audi
Verba libens; animi est istud amantis opus.
The vocabulary is keyed to the DCC Latin Vocabulary list. There is only one word in this poem that is not on the DCC list:
corrigō, corrigere: correct, improve
libens (libentis): willing, glad
aliquis -quae -quod: some, any; si quis, si quid: anyone who, anything that
amō -āre: to love; amans -ntis m./f.: lover
animus -ī m.: spirit, mind
audiō -īre -īvī/-iī -itum: hear, listen to
ille illa illud: that
iste ista istud: that, that of yours; adv. istīc or istūc: over there; istinc: from over there
opus operis n.: work
peccō -āre: commit a wrong, injure
sī: if
sum, esse, fuī: be, exist
tū tuī tibi tē: you (sing.)
verbum -ī n.: word