Je was op zoek naar: lesson to be learned (Engels - Latijn)

to be
ad esse non esse

used to be
frater antenatus

to be strong
fortis esse

to be,exist
sum esse fui futurus

lessons not to be learned in blood are quickly forgotten
lectiones in sanguine non discendae cito oblitae sunt

there is no one is good by chance: it is a virtue to be learned
nemo est casu bonus :discenda est virtus