Here is a continuance of that message in Romans specifically to the Gentiles:

Romans 11:16-24 (KJV)

16 For if the firstfruit be holy, the lump is also holy: and if the root be holy, so are the branches.

17 And if some of the branches be broken off, and thou, being a wild olive tree, wert graffed in among them, and with them partakest of the root and fatness of the olive tree;

18 Boast not against the branches. But if thou boast, thou bearest not the root, but the root thee.

19 Thou wilt say then, The branches were broken off, that I might be graffed in.

20 Well; because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear:

21 For if God spared not the natural branches, take heed lest he also spare not thee.

22 Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, if thou continue in his goodness: otherwise thou also shalt be cut off.

23 And they also, if they abide not still in unbelief, shall be graffed in: for God is able to graff them in again.

24 For if thou wert cut out of the olive tree which is wild by nature, and wert graffed contrary to nature into a good olive tree: how much more shall these, which be the natural branches, be graffed into their own olive tree?