Peter denied Jesus three times when Jesus was about to be crucified. Even after seeing Christ risen at least three times (see Lk 24:34; Jn 20:19, 26), Peter rebelled against the risen Christ by returning to the fishing business (cf Mk 1:17). Then, Peter made a fool of himself by jumping in the lake with his clothes on (Jn 21:7). Peter was a mess.
A few weeks later, Peter boldly witnessed for Jesus to thousands of people (Acts 2:41; 4:4). After being arrested for this witness, he even challenged "the leaders, the elders, and the scribes" (Acts 4:5) to repent of rejecting Jesus and to accept Jesus' name as the only "name in the whole world given to men by which we are to be saved" (Acts 4:12).
What happened to Peter? How did he change from the death of fear and sin into the life of freedom and faith? Peter was "filled with the Holy Spirit" (Acts 4:8). The Holy Spirit will eventually raise our bodies from the dead (Rm 8:11). That will be our last resurrection. Before that, the Spirit will raise us from the death of cowardice, rebellion, and selfishness into new, abundant, and eternal life.
By the Spirit, rise now so you will rise later. "Awake, O sleeper, arise from the dead" (Eph 5:14).