2) Make the hope of the gospel clearly known.
True hope in grief cannot come apart from the hope of the gospel. This is why the second and third portion of a funeral sermon focuses on Christ’s person and work. Whatever text you choose to preach, make sure you are able to focus on the clear elements of the gospel from it: God’s holiness, man’s sinfulness and deserving judgment, Christ’s perfect personhood and atoning work to save us, and our essential response to repent and believe upon Christ.
3) Call your hearers to respond to the gospel.
To do so appropriately and effectively, you must prepare by knowing as much as you can about your hearers as well as the deceased. You should assume Christians and non-Christians are present. You should assume they all have come with a preconceived understanding on how we receive eternal life. For example, I have done a funeral where 90 percent of those in attendance were devoted Catholics, another who were Mormons, and another where no one in the building had ever stepped foot in a church.
In every case, I explained the gospel clearly, called my hearers to repent of their sins, believe upon Christ and trust in him. Yet, in each of these different situations, I approached calling them to respond to the gospel differently, depending upon their preconceived understanding of the “good news.” Exhort them to grieve. Preach the gospel clearly and simply. Help them understand their need for Christ as death is before them. Call them to repent and believe.