Themes of grace and judgment come from the Spirit of God through the pen of Matthew. As Jesus invited people to find salvation in Him, He warned them of coming judgment on unrepentant sinners.
Some have done a disservice to evangelism by suggesting that witnessing to Muslims requires a special technique because they are almost impervious to the gospel. The good news is good news to Muslims too! We are to sow good seed among Muslims as well and pray for the harvest!
Philippians is a missionary prayer letter that begins with an answer to Paul’s prayer: he thanks God for your “partnership in the gospel,” or our teamwork for the gospel