This passage is set between Jesus’ ascension (40 days from the resurrection) and Pentecost (50 days from the resurrection). Jesus has left and the disciples are waiting for the Holy Spirit.

The Twelve - all were handpicked by Jesus and were witnesses to the five following aspects of belief in Jesus. [Thomas Oden from his book Classic Christianity]
1. incarnational reality
2. obedience to the law
3. teaching
4. ministry
5. death, resurrection, ascension and return

The only unique characteristic among the Apostles is their being personally invited by Jesus into the ministry. Instead of Jesus picking Judas’ replacement, he leaves for heaven and entrusts the duty to the disciples.

Jesus entrusts the church to be his hands and feet (John 14) and his fullness on earth (Ephesians 1.)

God trusts you:
Money
Time
Gifts
Relationships
His church

Witnesses are inherently reliable if:
1) Knowledgeable
2) Practicing
3) Understand they are a witness of faith and not the reason for faith