I looked it up as well, because I had a guess at which famous verse it was but didn't know it by chapter/verse.

The context of the verse, based on the surrounding verses, is that "simplicity with the Lord"[0] means accepting that what happens, or what will happen in the future, is from God and there's no need to try to figure out what will be out make sense of the uncertainty of life.

I think I can relate that to the GP's quote.

[0] translation to English my own, not sure what the language you saw was. Notably, the word used in the original Hebrew[1] can be translated as "simplicity" but also "wholeness" or "completeness". Maybe that works better? Also interestingly, in contemporary Hebrew, it means "naive"...

[1] תמים