It is true that satan knows who Jesus IS, but that does not mean he believes in JESUS's sovereignty among humankind. We cannot see JESUS as He now is in His glorified body, IN HEAVEN, but we believe on HIM WHOM GOD sent for our salvation.
I could also write that sentence as 'we faithe in HIM WHOM GOD sent' for our being born from above, born of the spirit. Faithing in JESUS as Savior and LORD evidences living faith, living belief, transformational faithing.
I believe this is what James was seeking to teach in his epistle. What happened on that first day of Pentecost following Jesus's ascension shows salvation is an immediate thing because the Holy Spirit came into the believers when they believed Jesus IS the One Whom God sent for their salvation. The scene in the house of Cornelius also shows salvation, being born from above is an immediate thing.
I wonder why folks never ask themselves or ask God about the ones who were in the crowd that day of Pentecost who did not believe and were not touched by the Holy Spirit that day? 3000 were added to His BODY / Church / Ekklesia that day, but certainly there were many than that who heard Peter's message. The Bible tells us of the 3000, but leaves out word regarding the rest of the mass who were listening to that strange sermon by an itinerate fisherman.
Paul wrote about the Bema Seat of Christ, IN HEAVEN, for those who believe in Whom God has sent for our salvation. If the teaching by Jesus, to Nicodemus, regarding the brass snake in the wilderness of Moses's day is any indication, there will be some surprises at that Bema Seat. Paul says, by inspiration from GOD, that a man's life works can be nothing more than wood, hay, and stubble, yet the man will be there in Heaven for the event.
My studied opinion on that is, the man was a believer who did not allow the Holy Spirit to raise him up in the way that he should go after he believed in the One Who GOD sent for his salvation. We may too often equate 'works' with acts of charity, etc. GOD may mean something a bit different, like the working out our salvation by being transformed through submitting our will to HIS raising.
The works of the spirit leadership manifest the faith of the man because only by faith are we transformed in this life. That transformation working out with fear and trembling is because it is God Who is in you, raising you up in the way that you should go! ... If you are born from above.
And in Acts 17:31 it refers to evidential warrant for believing:
Because he hath appointed a day, in the which he will judge the world in righteousness by that man whom he hath ordained; whereof he hath given assurance [pistis] unto all men, in that he hath raised him from the dead. (Act 17:31: KJV)