William MacDonald emphasizes that true fitness for heaven is not based on human merit or degrees of goodness, but solely on being in Christ. He explains that all humans are unfit for heaven due to sin, and no amount of good works can change that. The good news is that through faith in Christ, believers are made complete and accepted by God, as they receive Christ's righteousness. MacDonald asserts that every believer, regardless of their past, has the same standing before God because they are all equally in Christ. Thus, the only crucial factor is whether one has Christ or not, as that determines their eternal destiny.

“…in Him you have been made complete.” (Col. 2:10 NASB) Contrary to popular opinion, there are no degrees of fitness for heaven. A person is either absolutely fit or he is not fit at all. This goes counter to the common notion that at the top of God’s totem pole are good, clean-living people, at the bottom are the crooks and mobsters, and in between are those with varying degrees of fitness for heaven. It is an enormous mistake. We are either fit or we aren’t. There is nothing in between. Actually none of us is fit in himself. We are all guilty sinners, deserving eternal punishment. We have all sinned and come short of the glory of God. We have all gone astray and turned to our own way. We are all unclean, and all our best works are like filthy rags. Not only are we totally unfit for heaven, but there is nothing we can do by ourselves to make us fit. Our best resolutions and noblest endeavors cannot avail to put away our sins or to provide us with the righteousness that God demands. But the good news is that God’s love provides what His righteousness demands, and He provides it as a free gift. “It is the gift of God, not of works lest any man should boast,” (Eph. 2:8, 9). Fitness for heaven is found in Christ. Whenever a sinner is born again, he receives Christ. God no longer sees him as a sinner in the flesh; He sees him in Christ, and accepts him on that basis. God has made Christ to be sin for us, He who knew no sin, that we might be made the righteousness of God in Him (see 2 Corinthians 5:21). So what it comes down to is this. Either we have Christ or we don’t. If we have Christ, we are as fit for heaven as God can make us. Christ’s fitness becomes ours. We are as worthy as He is, because we are in Him. On the other hand, if we don’t have Christ, we are as lost as we can possibly be. To be without Him is the fatal deficiency. Nothing else can ever make up for this crucial lack. It should be clear then that no believer is any more fit for heaven than another believer. All believers have the same title to glory. That title is Christ. No believer has more of Christ than another. Therefore none is more fit for heaven than another.