Increase in the number of jobs in an economy: Central Bank raises interest rates? For example since the August job report came out, which showed hundreds of thousands ob jobs created. This will inevitable lead to the Fed to increase interest rates, but what is the motive behind doing this? 

Would this not simply lead to a decreased shift in consumption and be an attempt at stagnating the economy?
When people find jobs, they start receiving salaries and their consumption increases. Increased demand for goods and services leads to increase in prices, or inflation. Fed is expected to respond with a rate hike to keep inflation in check.