This Daas did some Vichaar on this Pauri. It is not possible to fully understand and comprehend sayings of Brahmgyanis. Here is a meagre attempt at doing some Vichaar on this Pauri:
ਭਲਾ ਬੁਰਾ ਸੈਸਾਰ ਵਿਚਿ ਜੋ ਆਇਆ ਤਿਸੁ ਸਰਪਰ ਮਰਣਾ॥
ਰਾਵਣ ਤੈ ਰਾਮਚੰਦ ਵਾਂਗਿ ਮਹਾਂ ਬਲੀ ਲੜਿ ਕਾਰਣੁ ਕਰਣਾ॥
ਜਰੁ ਜਰਵਾਣਾ ਵਸਿ ਕਰਿ ਅੰਤਿ ਅਧਰਮ ਰਾਵਣਿ ਮਨ ਧਰਣਾ॥
ਰਾਮਚੰਦੁ ਨਿਰਮਲੁ ਪੁਰਖੁ ਧਰਮਹੁ ਸਾਇਰ ਪਥਰ ਤਰਣਾ॥
ਬੁਰਿਆਈਅਹੁ ਰਾਵਣੁ ਗਇਆ ਕਾਲਾ ਟਿਕਾ ਪਰ ਤ੍ਰਿਅ ਹਰਣਾ॥
ਰਾਮਾਇਣੁ ਜੁਗਿ ਜੁਗਿ ਅਟਲੁ ਸੇ ਉਧਰੇ ਜੋ ਆਏ ਸਰਣਾ॥
ਜਸ ਅਪਜਸ ਵਿਚਿ ਨਿਡਰ ਡਰਣਾ ॥18॥The subject of this Pauri is not Ramayana or Siri Raam Chand but using their example, Bhai Sahib is proving the Gurmat principle that one gets praised or condemned based on one's Karma. If we do good Karma, we would get praised and if we do bad Karma, we would get condemned and slandered. In Siri Asa kee Vaar there is a Pankiti that goes as follows:
ਜੇਹਾ ਘਾਲੇ ਘਾਲਣਾ ਤੇਵੇਹੋ ਨਾਉ ਪਚਾਰੀਐ ॥(The kind of deed a person does, so the reputation of such person spreads)
This Pauri gives the example of Ravan and Raam who fought a battle. Ravan committed a bad act and incurred a black stain (ਕਾਲਾ ਟਿਕਾ) by taking away someone else's woman (ਪਰ ਤ੍ਰਿਅ ਹਰਣਾ). Till this day people remember his bad deed. On the other hand Rama followed Dharma and till this day his deeds in form of Ramayana are remembered and many people get inspired by his good deeds.
This subject of this Pauri is not Rama or Ravana or Ramayana but Bhai Gurdaas jee is making the point that one's reputation depends on one's deeds.
Kulbir Singh
ਸਤਿਗੁਰਬਚਨਕਮਾਵਣੇਸਚਾਏਹੁਵੀਚਾਰੁ॥