Baptism, for fundamentalists, is not a sacrament, but an ordinance. Since only an adult can be converted, baptism is not appropriate for infants or for young children below the age of reason.
Most fundamentalists say infants and young children are automatically saved, no matter what.
These commands are universal, not restricted to adults. Along with this forgiveness of sins comes an infusion of grace. It is this grace that makes the soul spiritually alive and capable of enjoying heaven. There are other benefits, too, such as the elimination of punishment due for sins and the right to special graces necessary to enable the baptized to fulfill his baptismal promises. But a consideration of these aspects of the sacrament would take us away from the narrow topic this tract is about, infant baptism.