William Burkitt on 2 Corinthians 1:5

Note here, 1. That the saint's sufferings are called the sufferings of Christ. The head suffers in the members, because the members suffer for the sake of the head.

Note, 2. That the saint's sufferings in the cause, and for the sake of Christ, are sometimes overflowing and excessive sufferings: The sufferings of Christ abound in us.

Note, 3. That as a Christian's sufferings are for Christ, so are their comforts and consolations from him; yea, their comforts do bear some proportion to their sufferings; as our sufferings abound, so our consolation abounds by Christ.