The “economy of grace” is God’s plan of salvation that reflects His infinite Goodness, Wisdom, and Love. We should trust God, even when we don’t fully understand His ways. God calls all to eternal salvation by His grace and only through Jesus Christ, and the one Church He founded. How God saves only through His Church is a mystery, but we can understand some things about it. People who are fully united with the Church (Catholics) have all the means of salvation: correct faith, fellowship, and sacraments. Those imperfectly united to the Church (other Christians) possess some of these means, and may attain salvation when they are in good conscience. God is the author of all truth and goodness, and those who earnestly seek after these, but have not heard the Gospel preached authentically, may be on the way to salvation. The goodness and truth they possess serves as “preparation for the Gospel,” and God will, by grace, complete what He has begun in them.
The parable of the workers in the vineyard teaches us that God calls some to salvation through faith in Christ later in life. This seems to be because God wants to use those He calls earlier to be instruments for the salvation of those He calls later. We become such instruments of salvation through faithful evangelization, intercession, and holiness — indeed, through “spiritual warfare.” By these means, God may save not only good people who do not know Christ, but even great sinners, even near the end of their lives, as is suggested by the “good thief” crucified next to Jesus.
The “bad thief,” on the other hand, is an example of those who refuse the mercy of God, commit the “eternal sin,” and condemn themselves to hell. Sin and Hell are also mysteries, and we need to continually trust in God’s goodness. Reflecting on the mysteries of God’s plan of salvation can help stir up in us holy dispositions that move us to strive for holiness, and the salvation of others.