Give me some guidance as to what I should do to derive a firm confidence and sure comfort from the articles of faith.
First of all, for each and every article of faith think about God’s promise that if you believe it in your heart and confess it with your mouth (Romans 10:9,10), God promises and gives you what is stated in that article.
For example, when you confess, “He suffered under Pontius Pilate,” you must not only remember the Passion story (for the Evil One knows it as well) but also believe that in this article God promises and assures you that He suffered for you and that it belongs to you as much as if you yourself had suffered.
Or, when you confess, “was crucified” (namely, for me), God promises you that He had His Son suffer for you (as Paul says in Galatians 2:20, “Who loved me and gave Himself for me”) and that this, therefore, belongs to you no less than if you yourself had been nailed to the cross when Christ was, to pay for your sins.
In sum, always remember that what is stated in each article is promised and given to you for salvation. That is why we also say, “I believe,” namely, that all this has happened also for my good and is promised and given by God to me as much as to the greatest of saints. In fact, you should be very certain that if you, poor sinner, had been all by yourself on the earth like a lone little sheep, nevertheless Christ would have left the ninety and nine already in heaven and come down to you from His heavenly glory to find you, put you on His back, and save you, as He Himself teaches in the gospel (Luke 15:3-7)
Caspar Olevianus, A Firm Foundation, pp. 12,13