'Prudently' in the Bible

And his master commended the unjust manager [not for his misdeeds, but] because he had acted shrewdly [by preparing for his future unemployment]; for the sons of this age [the non-believers] are shrewder in relation to their own kind [that is, to the ways of the secular world] than are the sons of light [the believers].

Conduct yourself with wisdom in your interactions with outsiders (non-believers), make the most of each opportunity [treating it as something precious].

In a similar way urge the young men to be sensible and self-controlled and to behave wisely [taking life seriously].