Here is a short quote that defines the inner call as being distinct , but NOT SEPERATE from , the external call of the Gospel , it will be noted that the effectual inner call is certainly soteriological in nature ;
How is it then, that people who are of a mind set that is hostile to God, and out of that hostility refuse to submit to God's commands (Romans 8:7) come to willingly belong to Him? How is it that people who dislike the knowledge of God so much that they traded it for something they know, deep down, is a lie (Romans 1:25), come to be His sons and daughters who cry out to Him, "Abba! Father!" (Romans 8:14, 15)? Well, if you're really looking up those verse in Romans 8, you probably already can see that the solution to our problem has something to do with the work of the Spirit. It is through the Spirit that we are brought into our relationship as adopted sons and daughters who can have the confidence of a child who knows that their father wants only good things for them and that he can always be approached in the boldest of ways. We come into this relationship of trust toward God rather than animosity through the work of the Spirit.
Calvinists (as Tim has reminded us) like to call this work of the Spirit the
inner call, the inner call being the work of the Spirit that is successful at bringing people to Christ, or the work that causes people who are existing in a state of hostility toward God to seek Him out and embrace Him. This is distinguished then from what is called the
outer call, the call of the gospel that goes out worldwide to all people, the call that encompasses those commands to seek God, a call that is always rejected unless it is accompanied by that inner work of the Spirit that turns people who are, as a result of the fall, naturally hostile toward God and His outer call to them, into people who see the value in the gospel and who embrace God and the call of the gospel.
We can see this always successful call here in Romans 8, too. Verse 30
tells us that there is a sort of call that always leads to justification:
....whom He called, these He also justified.... (NKJV)
The grammar leaves no room for this sort of call to be unsuccessful. Every person called in this way is justified by God, and since we know that we are not justified unless we believe, we know that everyone who is called in this way is successfully brought to faith. Those who receive this effective call come to embrace God and the gospel through faith.
We can also find this successful call in 1 Corinthians 1: 23-24.
http://everydaymusings.blogspot.com/2004/04/effective-call-or-how-people-come-to.html