Friends recalled John and Wanda Casias as spiritual soldiers who gave their lives to God and hearts to Mexico, where the American missionary couple was slain last week.
Hundreds attended the Wednesday service at Liberty Baptist Church in the Dallas suburb of Lewisville.
Pastor Dick Webster told those gathered that the Casiases "gave their lives for the cause of Christ." Webster added he wants to make sure their work continues.
The couple were found dead Jan. 31 at their home in a village outside Monterrey, about 95 miles south of the Texas border in an area plagued by violence.
Mourners already paid respects to the couple at the church in Mexico established by 76-year-old John Casias and his 67-year-old wife. Both were strangled with an electrical cord.