In a court case, the objective is to convince the jury of the truth. Witnesses are called to present evidence of what they have seen, heard and experienced. The case is won by the evidence of the witnesses.
Jesus said, "...when the Holy Spirit comes upon you, you will be My witnesses..." (Acts 1:8)
The "case" for Jesus is won by His people, through the Spirit, called as witnesses to present the evidence.
Evidence is the result of what is seen, heard and experienced. In Galations 5:22 & 23, Paul calls the evidence "fruit". The result of our experience with the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control.
Because each of us is uniquely created, the fruit will be evident in different ways at different times, but because it is from the same Spirit, it will be the same fruit.
As Christians, we are always witnessing. Our love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control is the evidence. By exhibiting this evidence in our daily lives, others will see and be convinced of the truth. The case will be won. Everyone will benefit.