What Does "Grieving the Holy Spirit" Mean?

I have heard the expression "Grieving the Holy Spirit" most of my Christian life and wonder if you could give me more detail.

The expression relates to Paul's words in Ephesians 4:30 - "Do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption." Since the Holy Spirit is a holy person who dwells within the believer, He will be grieved by any sinful actions. Read also verses 29 and 31 for Paul's description of some of the words and deeds that may bring pain to God's Holy Spirit.

When a person has been saved, is that person "Spirit-baptized," or "filled with the Holy Spirit," at the some moment? Is "speaking in other tongues" evidence?

Spirit-baptism, or Spirit-filling, may or may not occur at the time of salvation. The first disciples in Jerusalem had been saved (see John 20:22) for some time before they were Spirit-baptized, or filled with the Holy Spirit (Acts 1:8 and 2:4). Years later, in Caesarea, the Holy Spirit was "poured out" (equals "baptized") on Cornelius and his household (Acts 10:45) in conjunction with their coming to salvation. In both cases, in Jerusalem and Caesarea, speaking in tongues (Acts 2:4 and Acts 10:46) immediately followed. Tongues were specifically said to be evidence in Acts 10:45-46. Since then many people have spoken in tongues as confirmation of a profoundly spiritual experience.