That’s a good question. Sorry I missed replying to it, I had to head out. Why then?
Let’s go back a bit further, the First Council of Nicaea. In 325, which proclaimed the nature of Christ’s divinity. Why did they wait close to 300 years to have this council? Wouldn’t it have been pertinent to establish this doctrine right away?
It was meant to address the heresies at the time which revolved around Arian and his denial of Christ’s divinity. It’s not as if Christ’s divinity wasn’t proclaimed right from the very beginning, but that until then, it had been unchallenged.
The same is true of purgatory. Purgatory has always been understood to be as such, it just wasn’t proclaimed until Trent and Florence, when the doctrine was challenged by the Protestants, in the same way as Arius challenged the nature of Christ’s divinity.
We do not believe in the existence of purgatory because there is no evidence for it in Scripture. The Bible speaks only of two destinations for those who die—heaven and hell.
Jesus promised the thief on the cross, who certainly had not led an exemplary life, that he would be with him in Paradise immediately.
There is no need for purgatory. A person who has faith in Christ has complete forgiveness of sins. There is no more debt to be paid. A person who does not have faith in Christ has no forgiveness of sins. No amount of time in purgatory could ever pay for his or her sins.
By rejecting the completeness of Christ’s payment for sins, this doctrine robs Christians of the comfort they should have at the time of their own death or the death of a Christian loved one.