An English translation of the Quran - 9:37 Know that the use of the additional month causes an increase in rejection, for it is used by those who have rejected that they may misguide with it by making it lawful one year, and forbidden one year, so as to circumvent the count of what God has made restricted; thus they make lawful what God has made forbidden. Their evil works have been adorned for them, and God does not guide the rejecting people.
They made the first month one of the holy months and removed Ramadan from the four holy months. Thus they make it lawful what is forbidden one year. The next year they make forbidden what is lawful!!
For those who don't know. They make Muharram forbidden and part of the four Holy months, the first month according to the current Arabic calendar. They removed the (9th) month Ramadan, from being part of the four Holy months.
I learned from the Quran that the last four months to perform Hadj in of the year are the Holy months. Starting from Ramadan, until Dhul Hidjah.