How does God's call through messengers work according to Reformed theology?

In Reformed theology, the call of God comes through His ordained messengers, who preach the gospel as it is written in Scripture. The importance of this call is emphasized in the assertion that faith comes by hearing, and hearing by the Word of God (Romans 10:17). These appointed messengers may not meet human standards of worthiness or ability, yet they are entrusted with the powerful task of proclaiming the Word of God. Their role is vital to communicate the gospel, which is the exclusive means by which God draws His elect, affording them the opportunity to respond in faith.