I have almost never heard a CRC pastor include an invitation to commit to Jesus or offer any follow-up for those who might be seeking. Why?
There is a reason, and it depends on how different branches of Christianity think about the purpose of sermons. In the Reformed tradition, the primary aim of sermons is not conversion, but teaching doctrine to people in the church. Historically, because pastors were mostly preaching to the converted, the emphasis was on making sure that their congregants did not make the kind of errors Reformers believed the medieval Catholic church was making—things that triggered the Reformation in the first place. The CRC’s long history of preaching the Heidelberg Catechism, which explains Reformed doctrine, comes out of this concern.
This is in contrast to the more historically recent Pentecostal church, for example, or those in the revivalist tradition, where preaching is viewed as a call to repentance to those who have never believed and to those who might be backsliding into sinful ways. Sermons became reminders of congregants’ need to recommit or to accept Jesus in the first place. Altar calls came out of this kind of preaching.
So, these traditions have significant differences in what they want the sermon to accomplish. It is possible, of course, to educate a congregation about the Bible and about doctrine while including an invitation to commit to Jesus. Scott Hoezee, director of the Center for Excellence in Preaching at Calvin Theological Seminary, says that their training strives to do exactly that. Pastors should strive to craft sermons that are “life changing” for the believers and unbelievers. So, while a sermon might not seem like an altar call, Hoezee says, “every sermon needs to preach the gospel and inspire people to want to be part of Jesus’ grand program.”