Hello
I entered the usa legally by marriage and I have my green card. We had two kids have US passport, my husband also has his citizenship. We left the united states before applying for my American passport, I was very much eligible for doing that and it's being for years and I am still outside the united states. Is there any problem in entering the country again and live there ?

You answer is appreciated.

Um... Mariage doesn't give anyone the legal right to enter on its own.

However you did get a green card... and that did. However since the laws have changed... we need to know how long you were outside of the USA. If you were outside the USA long enough, it would have been canceled, and if it was, you will have to go through the process all over again.

I am confused by your statement "We left the united states before applying for my American passport". A prerequisite for applying for a U.S. passport is that you already have U.S. nationality. So did you or did you not become a U.S. citizen (naturalize)? Naturalization is a long process that you have to apply for.

If you are a U.S. citizen you can enter the U.S. and live there at any time. If you did not become a U.S. citizen, and were only a permanent resident when you left, you likely abandoned your permanent residency because you didn't maintain residence. Your husband would have to petition for you to immigrate to the U.S. again.

I have my permanent resident and I left the united states 4 yeas ago, can I go back and renter the country with my green card witch I still have in my hand ?

That green card has been canceled by the government and is no longer valid if you have been out of the country for 4 years. You will have to reapply to get another.

When you leave US for more than 12 months without getting travel document approved, your green card is automatically revoked. You need to file SB-1 visa (return resident) at the consulate and start green card process again as soon as you arrive in US.

I have my permanent resident card and will expires on July 2016, still married to my us citizen husband and have to us citizen kids from that marriage. Is there any concerns entering the us after 4 years of living outside the country?

Yes you do need to be concerned, they will probibly refuse you entry as your green card will probibly be cancelled for not residing in the USA for anywhere close to the minimum required time for the last year much less over the last 4 years.