en_tn/1ti/06/17.md

Tell the rich

Here "rich" is a nominal adjective. It can be stated as an adjective. AT: "Tell those who are rich" (See: rc://en/ta/man/translate/figs-nominaladj)

in riches, which are uncertain

"in the many things that they own that they may lose." The reference here is to physical objects.

all the true riches

"all the things that will make us truly happy." The reference here may include physical objects, but it more likely refers to states like love, joy, and peace that people try to obtain by means of physical objects.