The Greek word "Paraclete," which Jesus uses to refer to the promised Holy Spirit, can be translated as "Defense Lawyer." Picture yourselves in the place of Jesus' disciples. After following the Master for three years, He tells you that He is suddenly leaving you tomorrow. But that's not all: as His replacement, you're getting a lawyer! We can understand why His disciples, who had recently heard Jesus publicly vilify lawyers (see Lk 12:46-52), would be "overcome with grief" (Jn 16:6) at this double whammy.
However, those who follow Jesus desperately need to be defended. Paul and Silas found this out at Philippi. They were seized and dragged "into the main square before the local authorities," who "turned them over to the magistrates" (Acts 16:19-20). Before they could speak a word in self-defense, they were flogged severely, thrown into jail in maximum security, and chained to a stake like animals (Acts 16:22-24).
At this point, Paul and Silas placed a call from their "cell-phone" to their Defense Lawyer, the Holy Spirit. Since the Lawyer already understood the specifics of the case, Paul and Silas only had to converse with their Lawyer in His native language: tongues, prayer, and praise (Acts 16:25). The Holy Spirit appealed the case directly to the Judge, the Father, and the verdict "innocent" was reached immediately. The Holy Spirit sent an earthquake to set the prisoners free, converted the jailer and his family, and vindicated Paul and Silas publicly (Acts 16:26ff).