Why worry about heretics and not pagans?

Two things which define the sum total of Christian history: Election and Volition

We see this tension already in Paul

But when God, who had set me apart before I was born and called me through his grace, was pleased to reveal his Son to me, so that I might proclaim him among the Gentiles, I did not confer with any human being, nor did I go up to Jerusalem to those who were already apostles before me, but I went away at once into Arabia, and afterwards I returned to Damascus. Gal 1:15-17

Paul, called (elected) was sent to proclaim in foreign lands

• A sense of election: God's chosen people, chosen from within the nations. (Do not underestimate the psychological effects of knowing you are chosen/called)
• A sense that Christians have something no one else does (Scot's worry about latent and lurking gnosticism)
• Aquinas: Belief depends on the will (voluntas) and cannot be coerced
• Yet, will alone isn't enough; we must be of God's elect too

Yet, worry of heretics and false gospels is there from the beginning

But even Titus, who was with me, was not compelled to be circumcised, though he was a Greek. But because of false believers secretly brought in, who slipped in to spy on the freedom we have in Christ Jesus, so that they might enslave us—we did not submit to them even for a moment, so that the truth of the gospel might always remain with you. Gal 2:3-5