Adam Clarke on Luke 21:5

Goodly stones - Or, costly stones. It has been thought by some that this relates not so much to the stones of which the temple was built, as to the precious stones with which it was decorated. For an account of the stones of the temple, see on Mar 13:1 (note).

And gifts - Or, consecrated things, αναθημασι. Αναθημα properly signifies a thing consecrated to sacred uses: Αναθεμα signifies a thing devoted to a curse, or to destruction. They both come from the same root, ανατιθημι, I lay up, separate; and though two meanings cannot be more opposite than those assigned to these words, yet in the words themselves a short vowel (ε) in the place of a long one (η) makes all the difference between blessing and cursing.