A brief biography of Peter, one of the first disciples, showing his calling by Christ (and partial response), then his conviction of personal sin, his realisation of Christ's divinity and work, and the critical stage - the full dawning of faith and surrender.

The duty and treasure of kindness toward God's people, its impediments constrasted with the great motive - the full readiness of the nature of Christ's love to us, and how He yielded Himself up for eternity. Also the necessity of cleanness, and the pitfalls of jesting. 

The apostle's appeal never to grieve the Holy Spirit. Here are the sins that do, causing Him to withdraw from (but never leave) us. Here also is what the sealing of the Spirit means for us, and the folly of undervaluing His grace.

Formative in the sense that in addition to being deeply offensive to God, they form deep roots in the character, promoting other sins and shaping the whole person, whereas new opposite virtues (performed by the Lord's help) lead to lifelong blessing and usefulness.