Concerning Paul ... Ok, IF you are a believing, faith filled, finished works of the Cross...?

Jesus died, was buried and arose three days later for your salvation Christian how can you , 1. ignore the teachings of Paul ? 2. Say Paul is NOT Holy Spirit inspired ? when in FACT 1. the four gospels do NOT teach the *finished* works of the cross.. 2. Peter OKs Paul's teachings .. Sorry, I do NOT get this type of thinking... either you believe in the *finished* works of the cross for salvation or you do not... there is NO in-between... Mathew, Mark, Luke and John do NOT teach it... sooooooooo, Unless you believe Paul WAS the apostle to the Gentiles the finished works of the Cross means nothing, because HE is the ONLY one who teaches it..... so, ok, explain please.. I am just curious how people come to believe in the works of the cross with out Paul ??? go in peace..... God bless