Daniel 2:43 (ESV)

43 As you saw the iron mixed with soft clay, so they will mix with one another in marriage, but they will not hold together, just as iron does not mix with clay.

Another way they will try to form great empires and also unity is through marriage alliances. Marriages between certain people are used to build up greater influence and stronger empires – especially marriages that bind certain royal houses and certain countries together - all in an effort to rule over larger areas. Both the politics of toughness and the politics of being tied together by marriages will not truly lead to a lasting, strong empire. Again, iron and clay do not mix. They do not form a strong connection. Time and again fractures occur. We also see this in recent history. The continual disintegration of empires will characterize world politics until Christ returns. Thus it becomes clear again and again that every human power and empire does not last forever. It will prove impossible to create an everlasting state of strength and wellness. For any kingdom that is good in all respects, we need to look to Christ’s eternal Kingdom, which is coming.