I found this poem in the collection Philosophia Patrum edited by Julius Wegeler.
Si videas fratres inter se bella gerentes,
Neutri confer opem, sed eorum corrige mentem.
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:
corrigo, -ere, correxī, correctum - correct, improve, straighten
bellum -ī n.: war
cōnfero -ferre -tulī -lātum: collect, bring to
frāter, frātris m.: brother
gero gerere gessī gestum: bear, manage; bellum gerere, wage war
inter: between, among; during (+ acc.)
is ea, id: he, she, it; eō, there, to that place
mēns mentis f.: mind
neuter, neutra, neutrum: neither of two
ops opis f.: assistance, resources
sed: but
sī: if
sui, sibi, sē: him- her- itself
video -ēre vīdī vīsum: see