The Galations forgot that salvation is in Jesus alone, and tried to add works.
Paul reminds them that Jesus is the right person, in the right place, at the right time, and in the right way.
The fullness of time and waiting - people are stuck until Jesus arrives.
The right person - understanding the problem faced by people lets us understand that Jesus is the only solution.
Before we come to Jesus we need to understand why he is necessary.
God takes his time to lay out his standards, promises and meanings.