Predestination Destroys Legalism
Predestination destroys legalism. If the whole of salvation, in all its parts, is understood to be by Christ alone, it leaves no room for boasting or trusting in ourselves, even partly. It strips us bare and forces us to abandon all hope in self-effort or rules to attain a right standing before God ... It shatters our self-complacency and causes us to renounce our self-righteousness. It makes us cover our lips and utter God is God and I am not (Rom 9:15, 16). That is why the Scripture declares: "It is because of Him you are in Christ Jesus, who became to us wisdom from God, righteousness and sanctification and redemption, so that, as it is written, “Let the one who boasts, boast in the Lord.” (1 Cor 1:30-31)
This is not to say that predestinarians cannot be legalistic. Human beings always find any way, Reformed people included. It means to say, rather, that if UNDERSTOOD CORRECTLY the doctrine of salvation by Grace ALONE in Christ ALONE will have the real effect of stripping us of legalism etc. Again only God's grace can do so. The true effect of biblical predestination will have on someone who beholds the majesty of God and is struck down by the fact that God will have mercy on whom he will have mercy is to say, I have no hope in myself, and justly deserve God's wrath save for the mercy of Christ alone who gives me everything I need for salvation, including a new heart to believe (Deut 29:4, 30:6; John 6:63, 65).