Although we typically think of publishing contracts in conjunction with book publishing, some periodicals also offer contracts. Such contracts are usually short—about a page—and simply identify the article by name, indicate what rights are being purchased, the amount of payment, scheduled date of publication, etc. I’m only aware of a few Christian publications that use them, but there is no reason to feel nervous about such a contract as long as it spells out the terms exactly as you expected them to be. If they differ from your understanding of the agreement, ask for an explanation and/or necessary changes in the contract. Do not sign it unless you agree with the terms.
Realize, too that you are not obligated to sign such a contract because they offer it. You always have the option of not selling the manuscript if you would be giving up too many rights or not being paid a fair payment. You need to be as careful about signing a publishing contract as you would be about signing a contract in any other area of business.