Understand God's word and using it in the right time and places

Acts 1:15-26
In those days Peter stood up among the believers and said to other group numbering about a hundred and twenty.
Brothers, the Scripture had to be fulfilled. Judas did what the Holy Spirit spoke long ago through the mouth of David concerning him. (at Psalm 69:25)
Therefor it is necessary to choose one of the men who have been with us the whole time the Lord Jesus went in and out among us, become a witness with us of his resurrection.
So they proposed Joseph called Barsabbas and Matthias, and they cast lots an the lot fell to Matthias; so he was added to the eleven apostles.
As far as we know, this is the last time the apostles use the time-honored method of casting lots. It is not just a 'lucky dip' - the decision is made after much prayer.
The 12 apostles parallel the 12 tribes of Israel, so the number must be made up.
The twelfth man must have been with Christ throughout his earthly ministry, and have seen him after the resurrection.
Why?
Peter wanted to explain that Jesus was died and resurrection as the Scripture says. And Judas was did the evil thing predicted by Holy Spirit, but the apostles needed to be filled the twelve for 12 tribes of Israel and the twelfth had to be chosen to witness Jesus' resurrection.
Peter has brave and familiar with the scripture, he can stood up to speak to the group, reminded all of these happened by the arrangement of the Lord, they should come together and continue the work of Jesus Christ.
Peter used the scripture for he familiar the God's word and used it in the right place and right time.
How?
Pray to the Lord let me have more Holy Spirit may understand the word of God and using it in the right time and places.