You have taken Col 1:24 out of context by thinking this verse refers to individual salvation. Paul is talking about how he must suffer in order for the gospel to be spread around the world - to increase the body - the church.
Jesus’ sacrifice was sufficient for salvation, but the suffering of missionaries is needed in order to bring the Gospel to unbelievers.
You still haven’t indicated how you can reconcile all of the other Bible passages that clearly indicate the atonement of Christ was complete and sufficient.
I disagree and since you don't have a defining authority supporting you my opinion is just as valid as yours.
Jesus’ sacrifice was sufficient for salvation, but the suffering of missionaries is needed in order to bring the Gospel to unbelievers.
I'm sorry bringing the gospel to unbelievers is classified as a work and is adding to Christ's sacrifice, you have just contradicted yourself twice in one sentence.
You still haven’t indicated how you can reconcile all of the other Bible passages that clearly indicate the atonement of Christ was complete and sufficient.I have you just refuse to see the truth. Father of five and I have both shown you more than enough evidence.