I was reflecting that at Pentecost, it's easy to focus so much on the transforming power of the Holy Spirit in the lives of the apostles, that we (or at least I) forget that they still had their human weaknesses to contend with. When I lose sight of that, I get a little extra discouraged over my own spiritual cluelessness... As usual, St. Peter is the one who puts things in a different light. The Holy Spirit did come upon him so strongly that the cowering man who "did not know" Jesus was breaking the door down to go into the middle of city and proclaim Jesus as the Lord. But down the road a piece, Peter waffled when some of the Jerusalem community reproached him over the way Gentiles were being admitted to the Church. And even the "Quo Vadis" legend hints that Peter was a little too ready to flee imminent martyrdom in Rome.
The Holy Spirit didn't just come and go in Peter's life: the Spirit came for a purpose, the preaching of the Gospel. Peter's human weakness was still there, underlining the fact that "the surpassing power is from God and not from us."