My father always told me to be brave and cheerful.

Literal

Father [topic-は] me [to-に] always brave-and cheerful be [quotative-と] said.

勇敢で快活であれ — であれ is the imperative of the copula である, giving a literary/formal command. 勇敢 (brave) and 快活 (cheerful) are na-adjectives joined with で.