As to the good thing given. It is abstract; the object is not to day what is given, but the manner of God's dealing. What is given is caused to be in abundance. We may say, also, 'he shall be in abundance,' a word used of the thing and of the person possessing it
i.e. what is wanting is supplied and so 'filled up.' Since Esaias's time there had been much of this, but the rejection of Christ completed and filled it up. 'In them' has therefore the sense of 'as to,' 'in their case.' 'By' would cast more on their act and responsibility: epi seems to have been introduced to avoid this sense of it.
Or 'were stumbled at him,' but the word 'stumbled' is too weak. The root word in Greek, skandalon, is literally 'the catch of a trap,' that makes it fall when touched. It is generally the occasion, or means, of getting into an evil case, not a stumbling-stone. See chs. 5.29; 18.6.