Galatians 4:2 He is subject to guardians and trustees until the time set by his father.
“He is subject to guardians and trustees” The words used here for “guardian” and trustee” are much broader and have more force than the word that described the “pedagogue” that the parents left “in charge” of the child back in Galatians 3:24. Just as a slave had to be under the authority and control of a master or owner, a child was under the authority of a guardian. This was, of course, usually the parent – usually the Father. But if his parents were dead, and the child was still a minor, Roman law required the child to be placed under a legal guardian (remember from 4:1 – a child has no rights, he is like a slave). The guardian would be appointed and named through the father’s will, or, if not specified, Roman law provided that the nearest living male relative on the father’s side of the family would serve in this role.
The world for “trustee” is translated in other versions of the Bible as “manager” or “steward.” This is quite similar in concept to a fiduciary trustee as understood in the modern legal system. This concept is comparable to the overseer of slaves on an early 19th century southern American plantation, or a foreman on a construction site, or the vice president of a corporation. In the context of Paul’s time, this would have been either a slave or a free man who wielded considerable power and authority. Similar concepts in other places in the New Testament are the vineyard owner’s foreman in Matthew 20:8 and the “manager of Herod’s household” in Luke 8:3. But whether a guardian or trustee, this is a much larger concept then what was essentially a babysitter, or Kindergarten teacher, or coach that was the pedagogue's role in Galatians 3:28. This is REAL authority. Paul will expand more in 4:3 on how this “authority” affected us in our spiritual lives.
“until the time set by his father” The father’s last will and testament, as the instrument which appointed the guardian, controlled how long the guardian would have authority over the child. If not specified, it would only last until the child reached majority. But often, a parent proscribed a longer time period. A father who knew his son wasn’t very responsible might make a guardianship that lasted well into the child’s adult years. The timing for when the child could call the shots was always set by the Father. This analogy works on a multitude of levels – not just for the basic issue of salvation and coming into God’s kingdom, and into a relationship with Jesus, but in the entire maturation process in our walk with God. Every step in the kingdom, all growth, every blessing, the “desires of our heart,: even the things God wants us to be responsible for – we will not come into them until the time “set by the Father.”