What is a pattern in the context of 1 Timothy 1:16?
In 1 Timothy 1:16, a pattern is the outline of the original—the first. Paul's case is the first, so Christ's mercy, longsuffering, and grace shown to him become the model or example. A pattern is what you use to cut out the first piece of material.
Les explains that Paul calls himself the chief of sinners, meaning the head of the line or preeminent one, not something bad. Then in 1 Timothy 1:16 Paul says he obtained mercy so that in him first Jesus Christ might show forth all longsuffering for a pattern. Les illustrates this with sewing: when making a dress, you use a pattern, and the pattern is the outline of the original, the first. If you are going to make three dresses, you use the pattern to cut out the first piece of material.
Howbeit for this cause I obtained mercy, that in me first Jesus Christ might shew forth all longsuffering, for a pattern to them which should hereafter believe on him to life everlasting.