“A prayer chain is a group of people who share prayer requests and commit to pray for needs as they arise. It’s called a “prayer chain” because the individual members are “linked” by prayer, and requests make their way from one person to another, following the “chain.” In a prayer chain, each link represents one person committed to pray for the needs of others. The more “links” in the chain, the more people are praying for the needs or struggles of others. The imagery of a chain also underscores the strength of God’s people who are united in prayer.”

(https://www.gotquestions.org/prayer-chain.html)