Question: I am struggling with some of the things I am being told in the [denomination name withheld] church. Namely, only those who join this church can be saved, and only those who tithe are members in good standing.
Response: Peter lesson #27 has a lot to say on these matters, as does the special, "Read your Bible: Protection against cults". Claiming to be the "only way to salvation" is a typical cult approach. When recruiting followers, these types of groups (I hesitate to call them "churches") often put it to the would-be proselyte that this is his or her "last chance" - that is, they use the same sort of pressure sales tactics one might expect to encounter in a used-car lot. Rest assured, no group is THE Church exclusively, even if they are truly following the Lord (and claiming to be the only ones is clearly a heretical point of view). All living believers in Christ, regardless of what humanly concocted organization they belong to (if any) constitute THE Church on earth. Salvation is based upon faith in Jesus Christ, not upon membership in any organization. This cult-type approach you describe is often effective because it appeals to the normal human drive to "join" something bigger than oneself and so provides a (false) sense of security (which I call "institutional security" in Pet.#27). In reality, our security comes from faithfully following Christ, not from membership in any religious (or other) organization, regardless of whether such groups make this false claim. This approach of claimed exclusivity for its members is not only horribly incorrect (it shifts the issue of salvation away from Him who is the only truth, and the only way to eternal life: Jn.14:6), but is also symptomatic of individuals (especially in the leadership) who clearly have no genuine concern for the spiritual well-being of their membership. Rather than salvation and spiritual growth in Christ, these types really have as their first priority the domination and control of their members. Please see also the following links:
Salvation and Church Affiliation.
Aspects of the False Doctrine of Institutional Security.
God's Free Gift of Salvation
Three False Doctrines that Threaten Faith.
Mega-Churches, Emergent Christianity, Spirituality and Materialism.
Characteristics of the New Religion of Antichrist.
The Local Church and Personal Ministry IV
The Local Church and Personal Ministry III
The Local Church and Personal Ministry II
The Local Church and Personal Ministry I
Your mention of "tithing" is also a sure sign of a non-biblical and non-spiritual modus operandi. For the issue really is not whether tithing is still legitimate (it is not, by the way), but rather that those who make a high priority of putting this (false) yoke upon their membership are almost without exception really only interested in one thing: money. And as our Lord assured us, you cannot truly be serving Him if money is your main concern (Matt.6:24). Please see the following links for more information on that topic:
Is Tithing Net or Gross?
Tithing and the Book of Life.
As to your own individual situation with this group, may God give you wisdom and guidance, along with the courage and common-sense to follow it.
Yours in Christ,