Liturgical readings are available here.
The apostles, liberated from the prison during the night in a miraculous way, take their place in the temple area to teach and proclaim. The angel of the Lord charges them to tell the people everything about this life and they effectively do that.
The word of life is the word about the life of Jesus, but also the life of his followers. They share in his life; they are supposed to live the same life. The word of life and salvation preached to us is the message about Jesus that concerns us: our faith is a treasure, grace received from God, and proclaimed to us. But as the word became flesh in Jesus, so it must take real form in our lives. It must be incarnate in us.
Faith is not something theoretical, but very real. Faith transforms our lives to be more and more similar to the life of Jesus. If faith is reduced just to ritual, it might appear nice, but it fails its purpose. Faith is real only if it changes lives.