All doctrines opposed to Calvinism diminish the operations of the Godhead in the salvation of sinners. Any doctrine that diminishes the work of the Godhead in the salvation of sinners is an affront to the Gospel.
Christ’s blood is perfectly sufficient and absolutely effectual in atoning for the sins of those that are called. The thought that “Jesus loves everybody” or “Christ died for the sin’s of all people” denies this, and so denies the efficacious atonement of Christ, trading it for a post-acting agent only effective when mixed with man’s work — his “decision”. Christ’s sacrifice is useless without an act of man, if Calvinism be denied.
God’s divine calling is lowered to the status of pleading rather than an effectual calling (2Tim 1:9 w/ Eph 3:7) which leads to repentance and faith, when Calvinism is denied.
The Holy Spirit’s work of regeneration is denied altogether. Man is not thought of as dead before the Spirit’s work (as Scripture teaches Eph 2:1), but simply sick. Man just needs a pick-me-up, not regeneration, if Calvinism be denied. Ezekiel 37? They’re just really, really sick.
When Calvinism is denied every operation of the Godhead in man’s salvation is diminished or excluded. Faith is not considered to be the work of God (as in Eph 2:8), but the work of man. Christs sacrificial work and atoning blood is useless without man’s decision. The Father’s calling is impotent without man’s decision. The work of the Spirit in regeneration isn’t necessary, because man is more alive and able than God thought he was.
The Father is weak, Christ is a failure, and the Holy Spirit is useless in salvation if Calvinism be denied.
Calvinism is much more than the opinions of an old dead guy. It is the opinion of many saints of old as they diligently studied Scripture, of Paul and the other Apostles, of Christ and the whole Godhead. The doctrine will live forever, while others come and go, for Christ’s Kingdom will advance and the doctrine with it.