We see here that Satan filled Ananias's heart to lie. Satan's influence is subtle and I highly doubt that Ananias had any idea that Satan was influencing him. It's the same with Judas, who betrayed Jesus for thirty pieces of silver (Matthew 26:15), but probably didn't think in his mind that he was being influenced by Satan and doing his work (John 13:27). Elaine Pagals, in an interview with Stephen Colbert, erroneously thought that there was a contradiction with the different accounts on why Judas betrayed Jesus, but one doesn't nullify the other.
Lying to the Holy Spirit is on par with lying to God. This is a clear indication that the Holy Spirit is indeed God, same way the Father is God and Jesus is God. It is also clear, despite the claims of the Jehovah's Witnesses, that the Holy Spirit is a person. Only a person can be lied to. Impersonal, non-living powers or energies cannot be lied to.
This verse, among many others in the NT, also shows that God still judges wickedness and carries out justice in ways that we might consider "extreme." He didn't just stop being "wrathful" and start being loving in the four hundred years between the testaments. God doesn't change (Malachi 3:6, Hebrews 13:8). These people are examples to us, showing the seriousness of sin, but also how gracious God is that He doesn't justly do this to all of us. He instead sent Jesus to die for us so "that whoever believes in him should not perish but have eternal life" (John 3:16).
