First of all, this subject is much too vast to be answered in a FAQ section, so to get a more detailed response, you can go to this page in the website.
Ecumenism is the process of "uniting" the Churches together.
You say, what is wrong with uniting Churches ? Is that not a good thing ?
Amos 3:3 states, "Can two walk together, except they be agreed?"
If you are going to unite Churches, then surely there must be some sort of common ground, on which to unite.
The basic, fundamental truth, by which you can judge whether a Church or a group agrees with the Word of God, is by what it teaches on salvation, or forgiveness of sins. This of course is vital, in that it deals with the future of men and women's souls. So it is so important that we get it right.
The Roman Catholic Church teaches a variety of methods: penance, confession to a priest, praying to saints or to Mary, the mass, to name a few - none of which are found in the Word of God. There are, of course, other major doctrinal differences.
The Word of God teaches, note this carefully please, (the verse speaks of the Lord Jesus Christ) :
"Neither is there salvation in any other: for there is none other name under Heaven given among men, whereby we must be saved." (Acts 4:12)
The only way to obtain forgiveness of sins, is through repentance and faith in the Lord Jesus Christ. There is no other way. To claim that there IS another way, is false.
Therefore, there can be no unification with such a system that is in stark contrast with what the Word of God plainly teaches.
But, equally, Protestant Churches, who would teach any other way of salvation, we also can have no fellowship with. If a "Protestant" Church teaches salvation through good works, Church attendance, or the sacraments, then this is also not found in the Word of God.
The Bible says, in Proverbs 23:23, "Buy the truth, and sell it not...."
We need to get back to the Bible. Search out the Word of God. Its truths are plain and simple.
To any Christian who would find themselves in an ecumenical Church, we would ask you to examine for yourself, and see if what we are saying is true.
We are not seeking to win you over to the Free Presbyterian Church (while of course we would love to have you with us ! ) All we seek is, (if your Church is in the ecumenical movement), for you to come out from the system of ecumenism and apostasy (for they go hand in hand), and take your stand for the Lord Jesus Christ and His Word.
Can you remain within a system which is so contrary to the Word of God and seeks to water down the Truth of the Gospel ?
To the voice that would urge you to stay in and "work from within the system," do you not hear the echo of the Word of God , "Come out from among them, and be ye separate" (2nd Corinthians 6:17).
One day, you will meet the Master, Face to Face. Will it not be good to say, "Lord, while I may not have been much, yet by Thy Grace, I took a stand for Thee, and for Thy Truth, and refused to be unequally yoked in a system which is contrary to Thy Word."
"Stay in......" .... "Come Out"....Which will it be ?
".. always abounding in the work of the Lord..." 1Cor15:58