That is a misapplication of that message. We are Christ’s body, yes. And we are to live according to His will by the spirit. We are not to imagine what that will is in terms of engagement with the world’s systems. We are to grow in His word to lead others to Him. Period. But salvation is of God by the Spirit through faith in the Son. That is the limit of bringing “this world closer to Heaven”. By personal interaction. This world is going to get worse and worse. The church will be raptured, the Tribulation will commence, bring Israel back to faith (1/3 of them anyway) and after 7 years, we will return with Him to reign in the 1,000 year millennial kingdom of Christ.
Nothing we do now can expand the kingdom (which doesn’t exist yet) or bring the world into line. We are to surely do our jobs as if unto Him, blessing even secular employers by our hard work. Be those jobs in any field.
But our “mission” is never to target the world and make it more Godly.