The Duty of Sonship

“But I say to you, Love your enemies and pray for those who persecute you, so that you may be sons of your Father who is in heaven.” (Matthew 5:44-45a)

In the Sermon on the Mount, Jesus explains what it means for us to be in a familial relationship with God. God is not simply a great Being to be worshipped; he is actually a Father to his people, and they are his sons. This familial relationship puts obligations on both parties.

For his part, God undertakes to care for us as his children. It is this rather obvious point that forms such a profound remedy for anxiety. As Jesus explains in Matthew 6, our Father knows of every need that we have. Therefore, we can busy ourselves with his kingdom work, because he will provide for our earthly needs. It is also this truth of God’s fatherhood that motivates us to pray: he is under obligation to listen to us as his children. Here again, Jesus expounds this within the framework of familial relationship: just as a good father doesn’t give bad gifts, so your heavenly Father will only give good gifts in response to his children’s pleadings.

But if God is under obligation as a Father, we are also under obligation as his sons. In Matthew 5:45 we are indeed commanded to ‘be sons of your Father who is in heaven.’ But what could it possibly mean to obey such an obligation?

We often think of a ‘son’ as one who is ‘born’ to a father, or we think of a son as one who ‘resembles’ a man because he bears his genes. Both of these are true, of course, but they are not the emphasis of Scripture. In the ancient world, the most significant idea behind ‘sonship’ was that a son resembled his father because he acted like him.

This makes sense when we understand how much time fathers and sons spent together in the ancient world; fathers and sons worked together in the fields throughout the day. ‘School’ was a foreign idea for many families, unless they were wealthy enough to afford a private tutor. More often, a son would learn everything about the world from his father. It was exceedingly odd for a son to choose his occupation – most sons took up the occupation of their father. The result is that sons generally resembled their fathers in more than simply their facial features: they acted like them as well.

This idea – that a son is one who resembles his father in his actions – provides the key to understanding nearly the entire ethical teaching of Jesus in the Sermon on the Mount. As sons of God, we are now under obligation to demonstrate his character. This means that we pursue peace with all men (5:9), reveal good works (5:16), pray for our enemies (5:44-45), demonstrate perfection (5:48), forgive others (6:14-15), and do the will of God (7:21).

This, then, is the obligation of the son: to demonstrate the character of his Father in heaven; to actually ‘be’ his son, as we are commanded by our Lord. And it is as we fulfill our obligation as sons, that we also take courage that God will fulfill his obligation to us, acting as our heavenly Father.