Prior to the Canons of Dort, the Counter Remonstrance of 1611 was the earliest and clearest representation of what is in modern times commonly referred to as the "five points of Calvinism.
He left behind a mixed legacy - a brilliantly gifted scholar whose career was marred with accusations that he had departed from the standard Calvinist interpretation of Romans 9, among other passages.
4. that to this end He has first of all presented and given to them his only-begotten Son Jesus Christ, whom He delivered up to the death of the cross in order to save his elect, so that, although the suffering of Christ as that of the only-begotten and unique Son of God is sufficient unto the atonement of the sins of all men, nevertheless the same, according to the counsel and decree of God, has its efficacy unto reconciliation and forgiveness of sins only in the elect and true believer.
7. that nevertheless the true believers find no excuse in this teaching to pursue carelessly the lusts of the flesh, since it is impossible that those who by a true faith are ingrafted into Christ should not produce the fruits of thankfulness; but on the contrary the more they assure themselves and feel that God works in them both to will and to do according to this good pleasure, the more they persist in working their own salvation with fear and trembling, since they know that this is the only means by which it pleases God to keep them standing and to bring them to salvation.
For this reason He also employs in his Word all manner of warnings and threatenings, not in order to cause them to despair or doubt their salvation but rather to awaken in them a childlike fear by observing the weakness of their flesh in which they would surely perish, unless the Lord keep them standing in his underserved grace, which is the sole cause and ground of their perseverance; so that, although He warns them in his Word to watch and pray, they nevertheless do not have this of themselves that they desire God’s help and lack nothing, but only from the same Spirit who by a special grace prepares them for this and thus also powerfully keeps them standing.
[5] God determined according to the good pleasure of his will to choose out of mere grace, these "elect" individuals and bring them to salvation within historical time.
[3][2] The doctrine of Irresistible Grace is outlined in point 5 where it is taught that the Holy Spirit uses the gospel preached broadly to many men to call and draw only God's elect.