Did they just say God can't do something?
Chapter and verse, please. I don't put limits on what God can do through others. My God is in the heavens; He does as He pleases. Jesus Himself said that He was *given* the authority to grant eternal life to others (John 17:2). God doesn't need to be given any authority.
Lexham Survey of Theology
If, as dynamic monarchianism insists, the Son and Spirit are not truly divine, then they are in no position to achieve and apply the salvation that humanity so desperately needs