“for then he would have had to suffer repeatedly since the foundation of the world. But as it is, he has appeared once for all at the end of the ages to put away sin by the sacrifice of himself.” (Hebrews 9:26, ESV)
When I lived in the snowbelt, keeping my black pickup truck clean was an impossible task. When a snowstorm or freezing-rain was on the way, the salt trucks were out on the major roads immediately. The salt melted the ice alright, but it left a salty watery film on the roads. You could not drive on the roads without splashing the salt water on the vehicle. Drive for an hour on the highway and the black truck took on a dirty gray appearance. The solution was to go through a carwash. The truck then looked beautiful for about a minute until you got back out on the road and immediately it got dirty again. The cycle needed to be repeated continuously. It was futile.
Consider the problem of the earthly Tabernacle. It was a copy of the holy places in heaven. The priest would go through the ritual of offering sacrifices year after year to purify the copy of the heavenly things. Sacrifices were offered repeatedly for sins, without perfect resolution of the problem. It was sort of like my truck in the winter. No matter how many times I washed it, it would not stay clean.
Here is where Jesus changed everything. The author of Hebrews tells us that Jesus did not enter the holiest place in heaven, having to offer himself as a sacrifice repeatedly. No, in His sacrifice on the cross, He offered Himself once and for all to put away sin. When Jesus died on the cross, bodily and shedding His blood, his last words were, “It is finished” (John 19:30). The word finished, tetelestai, means to bring to a close, to end. It means more than the sacrifice of Jesus and his life had ended.
The verb is in the perfect tense, which refers to an action completed that has ongoing effect. Jesus’ sacrifice on the cross was the final sacrifice for sin. There would be no further sacrifices needed to deal with the problem of sin. Jesus defeated death and the power of sin once and for all. We who have believed in Jesus and His finished work have been made beneficiaries of His death for us. He died for our sins and now we have access to God in Him.
In a way, we were like my truck. Impossible to keep clean and unpresentable to God because of sin. However, on the cross, Jesus became sin for us so that we might become the righteousness of God in Him (2 Cor 5:21). Now, unlike my truck we have been made clean from sin and acceptable to God. This is not because of anything good in us, but that Christ has clothed us with His righteousness. We are acceptable to God and have access because we are in Christ and He is acceptable.