How do we know that salvation is purely God's work?

The assertion that salvation is solely the work of God is grounded in scripture where we see that God, in His sovereignty, acts to bring about redemption. This is evident in Exodus 33:19 where He states, 'I will be gracious to whom I will be gracious.' Thus, the sinner’s ability to respond comes only after God first moves upon their heart. It is not based on any works or merits that we achieve, but solely on His grace through Jesus Christ, who fulfilled all righteousness on our behalf. This underscores the Reformed belief in total depravity—our complete inability to save ourselves, necessitating God’s initiative in graciously saving the elect.