William Burkitt on John 3:17

Observe here, That the salvation of sinners was the intentional end, and the condemnation of them only the accidental event, of Christ's coming into the world. The design of Christ's first coming into the world. The design of Christ's first coming into the world was to save it. The end of his second coming will be to judge the unbelieving part of it.

Observe secondly, That unbelief is the cause of the sinner's damnation; it is that sin which doth bind all other sins upon the sinner, and consigns him over to damnation; it is that sin which doth not only procure damnation, but no damnation like it; which is intimated in the next verse.