This is from the Institutio Puerilis of Marc Antoni Muret (1526-1585); you can read the book at GoogleBooks.
Nec cuivis sapiens, nec nulli credere debet;
Fallitur alter saepe, fidem sibi detrahit alter.
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:
dētraho -here, dētraxī, dētractum - drag away, remove, withdraw
alter altera alterum: other of two
crēdo -ere crēdidī crēditum: believe
dēbeo -ēre dēbuī dēbitum: owe, be obliged
fallo fallere fefellī falsum: deceive
fidēs -eī f.: trust, faith
neque, nec: and not, nor; neque . . . neque, neither . . . nor
nūllus -a -um: not any, no one
quī- quae- quidvīs: any one you please, no matter what
saepe: often
sapiens -ntis: wise, sensible
sui, sibi, sē: him- her- itself