The idea is that you maintain a "Unshakeable Spirit/Heart/Mind" w.r.t. your ultimate goal (whatever that may be) but still keep your everyday working mind aware, adaptable, not losing heart when difficulties arise but working through them all with a sense of calm purposeful focused action.

The Fudōchi Shinmyōroku states that as, the "Right Mind" is like free-flowing Water (useful in any situation since it can quickly assess, adapt and respond) while "Confused Mind" is like congealed water i.e. Ice (not useful since it is static, fixed form and not adaptable).

In modern terms, we can restate it as goal setting, long-term strategy vs. short-term tactics, maintaining composure and fortitude while working towards the goal unceasingly.

Happy New Year (bot or not!)