The issue between those who hold to the sincere offer and those who do not

The complainants put it this way:

In the course of Dr. Clark's examination by presbytery it became abundantly clear that his rationalism keeps him from doing justice to the precious teaching of Scripture that in the gospel God sincerely offers salvation in Christ to all who hear, reprobate as well as elect, and that he has no pleasure in any one's rejecting this offer but, contrariwise, would have all who hear accept it and be saved.

Let us try to define the difference between the complainants and Dr. Clark as sharply as we can.
The difference is not that the complainants insist that the Gospel must be preached to all men promiscuously, while Dr. Clark claims that it must be preached only to the elect. This would be quite impossible, seeing that no preacher is able to single out the elect and separate them from the reprobate in this world. They are agreed that the Gospel must be preached to all men.
Nor is the difference that the complainants openly deny the doctrine of reprobation, while Dr. Clark professes to believe this truth. We read in the Complaint: 'He believes - as do we all - the doctrine of reprobation'.
Again, the difference does not consist in that the complainants characterize the Gospel as an 'offer' of Christ or as salvation, while Dr. Clark objects to that term. If the term 'offer' is understood in the sense in which it occurs in the confessions, and in which also Calvin uses it (offere, from obfero, meaning to present), there can be no objection to that term, though, to prevent misunderstanding, it would be better to employ the words to present, and presentation.
Again, even though Dr. Clark objects to the word 'sincere' in the sense in which the complainants use that term, afraid to leave the impression that he preaches Arminianism, even this does not touch the real point of difference between them. That God is sincere in the preaching of the Gospel no one would dare to deny. As the complainants rightly ask: 'Would it not be blasphemy to deny this?'
 But the difference between them does concern the contents of the Gospel that must be preached promiscuously to all men.
It is really not a question to whom one must preach, or how he must preach, but what he must preach.
According to the complainants, the preacher is called to proclaim to all his hearers that God sincerely seeks the salvation of them all. If this is not their meaning when they write: 'in the gospel God sincerely offers salvation in Christ to all who hear, reprobate as well as elect,' their words have no meaning at all.
According to Dr. Clark, however, the preacher proclaims to all his hearers promiscuously that God sincerely seeks the salvation of all the elect. The elect may be variously named in the preaching: those who repent, they that believe in Christ, that hunger for the bread of life, that thirst for the water of life, that seek, knock, ask, that come to Christ, etc. etc. But they are always the elect.
We may define the issue still more sharply, and limit it to God's intention and attitude in the preaching of the Gospel with regard to the reprobate. - Herman Hoeksema, The Clark-Van Til Controversy