Do not go gentle into that good night.
Old age should burn and rave at close of day;
Rage, rage against the dying of the light.
Though wise men at their end know dark is right,
The ‘wild’ men are urged  not to go ‘gentle’ — what they are least likely to do. This contrasts with the previous stanza where the ‘good’ men are urged to ‘rage’. 
 The villanelle structure continues, with the third line of this stanza matching the third line of the first stanza.
Do Not Go Gentle Into That Good Night