The Christian sermon is Gospel preaching. We only preach the Gospel. Only the Gospel is the sermon, notwithstanding necessary admonishments of law and requisite exhortations toward sanctification.
The Apostle Peter’s monumental sermon on Pentecost declares the Kingdom purposes and divine saving work of the Father, Son, and Holy Spirit which culminates in the new world order with Christ in charge.
The season of Lent gives almost unparalleled opportunity for preachers to placard before their auditors the Cross of Christ and beckon Christians to take up their cross and follow Him.
The preached word ensured the work of the Holy Spirit, so long as it was the written word of the Gospel. Gospel preaching was the one domain in which we could be assured of the convicting, saving, and sanctifying work of the Holy Spirit.