Learn English – word for “small but powerful”

In my software development projects I use "todo" for the smallest unit of work, "task" for the next highest, which might be comprised of several todos, and "milestone" for the next, which is typically comprised of several tasks. A project, then, is made up of several milestones.

I know these are not stylistically elegant, but they are fairly commonly understood on the software projects I've worked on.

This may verge into theology here; but if you want to talk about the relationship of a deity to time, one common word is eternal:

: having no beginning and no end in time : lasting forever
: existing at all times : always true or valid

(merriam-webster.com)

Saint Thomas Aquinas, in his Summa Theologica, defines eternity (following the Christian philosopher Boethius) as

the simultaneously-whole and perfect possession of interminable life

and argues that this characterizes God.

If this is what you're looking for, use the word eternal.