Why did the disciples' attitude change after Jesus' resurrection?
After Jesus’ resurrection, the disciples understood that nothing could touch their eternal part, because if the Lord had been raised, they would be raised too. That changed their attitude completely, because men could take their physical lives, but they could not end their spirit life.
Les explains that before the resurrection, after the arrest and as Jesus was placed on the cross, the eleven had scattered like a flock of quail, practically running for their lives because they saw what was happening to their master. But after His resurrection their attitude totally changed. They now understood that nothing could touch that eternal part of them; if the Lord had been resurrected, they would be too. Knowing the crucified Christ had been raised from the dead, they could take His life—so what? They cannot end His spirit life. Paul had that same mindset: the resurrection power of Christ would keep him even through the trials and tribulations of his physical life.