Why does Paul keep using the phrase 'the power of God' in Romans?
Paul emphasizes the power of God because it is the same divine power that created the universe and was concentrated on believers the moment they believed, rescuing them from Satan's slave market; it is also the resurrection power that declared Christ the only begotten Son.
Les explains that with God it took all the power at His disposal to bring us out of Satan's slave market. As he moves through Romans, he stresses that the power of God is the very same power that put everything in the universe in place, and it was concentrated on every one of us the moment we believed. That power brought us out of the clutches of Satan's slave market. This is why Paul constantly refers to 'the power of God.' Les also ties it to resurrection: Christ was declared the Son of God with power according to the Spirit of holiness, and resurrection from the dead proved it. The psalmist's 'only begotten Son' terminology is not about Bethlehem but about His resurrection, when He became the truly only begotten Son. It was the power of resurrection. Many may believe Christ died on a Roman cross but struggle to accept He was raised; if we cannot accept that, we have nothing and are totally lost, because resurrection is the very basis of His power.