By teaching us to call upon the Father in times of distress, the Spirit convinces us that we are God’s children: The Spirit himself bears witness with our spirit that we are children of God.
Through baptism Christians know that we have died with Christ, and that we will also one day be raised along with him. In our own spirit we are now convinced that we can rightly call ourselves God’s children. This inner confirmation of that conviction only comes by the Spirit who motivates us to take refuge in our Father in the midst of attacks and suffering. Calling upon the Father proves that the Spirit of Jesus dwells in us and this confirms that we have indeed been adopted.
The ESV’s translation of the verb summarturein as bears witness with
is rightly opposed by Cranfield.1 After all, what witness can our own spirit have independent of the Spirit of God? In the Greek this verb can also mean to give a definitive witness.
It is the Spirit of God who gives a firm assurance to our spirit, not “with" our spirit. Less convincing, however, is Cranfield’s objection to the idea that the Spirit provides this testimony in the process of teaching us to call upon God the Father. For the Spirit does not provide us with this confirmation only when we pray, even if prayer also serves as a supplementary affirmation of this knowledge. The Spirit works our calling upon the Father as confirmation of our certainty that we have already been accepted as God’s children through faith.2
16 The Spirit himself bears witness with our spirit that we are children of God,