Francis discerned the Sultan's religious, cultural and political situation and circumstances. He greeted the Sultan as a child of Abraham and a brother. Francis presented the Good News, not to convert the Sultan, but to confirm Allah's universal loving and merciful fatherhood. Francis and his family were entrusted with the custody of the Holy Land.
Francis advised:
"The brothers who go [among the Saracens and other non-believers] can live spiritually among them in two ways. One way is not to engage in arguments or disputes, but to be subject to every human creature for God's sake and to confess that they are Christians. Another way is to proclaim the word of God when they see that it pleases the Lord." (Regula non bullata, chapter 16)
Preach the Gospel. Use words if necessary. Do so when it pleases God and makes every human creature, sinful though they may be, happy because Jesus says to all repentant sinners, "Today you shall be with me in paradise." (Lk. 23:43)