how can a person spend eternity in God's presence?
A person can spend eternity in God's presence because God has made provision for every human being to do so. The condition is to simply believe the gospel. Those who believe are able to spend eternity with Him, while those who reject it will not.
Les explains that there is an eternity to be faced, and God has made provision that every human being could spend it in His presence if they would simply believe the gospel. Many, however, will not believe because they do not want to be bothered. The surrounding passage stresses that this is not about dividing over human leaders like Paul or Peter or merely going by what Jesus said while He was confined to the Jew under the law. Instead, God now speaks through the apostle Paul, and grace takes its preeminence. No human teacher was crucified for us; Christ is not divided.