[Acts 1: 23So they proposed two men: Joseph called Barsabbas (also known as Justus) and Matthias. 24Then they prayed, “Lord, you know everyone’s heart. Show us which of these two you have chosen 25to take over this apostolic ministry, which Judas left to go where he belongs.” 26Then they cast lots, and the lot fell to Matthias; so he was added to the eleven apostles.]
In the book of Acts, we see the Apostles and disciples cast lots to determine who should be the replacement Apostle in place of Judas Iscariot. This is the last time in the Bible that lots are cast.
Because in Acts 2, the Holy Spirit is poured out on the disciples in the Upper Room. And after that, the floodgates are open and we have the Age of the Church, where people are indwelt with the Holy Spirit of God and He communicates with them personally. Sometimes, it is sort of like you said, our “conscience” speaking to our hearts what is right. But sometimes it is much more bold. It may be a voice, or through someone else’s voice. Maybe through a vision or dream He will speak. Maybe He will give someone a word or message for you.
Maybe the “silent” voice of God is really not silent, but the powerful whisper in the midst of fire and whirlwinds.
He is speaking, it is for us to have “ears to hear”.