Steve's barking; Why does the Fed have to Raise I t's interest rate?

I keep hearing that the Federal Reserve Board has to raise it's interest rate..
My question is why?
Is it because the Fed governors show that they are doing something?
There are those who claim that raising the rates help stave off inflation, but depending on the situation raising interest rates is inflationary in itself.( Inflating the cost of money).

Speaking of the Fed's I believe I heard some person say that when the Fed sells release the bonds to the general market a major problem would exist in the bond market. My question is we're is it written that the Federal Reserve board has to sell back bonds. Heck if it keeps the bonds in real terms it reduces the federal deficit.
( The Feds at the end of the day would give the money to the treasury. I understand that a very difficult thing to understand).