In this couplet new friends are compared to silver and old friends to gold.It is a common knowledge that gold is a more valuable metal than silver.Similarly,old friends are much more important than the new ones.While old friends have been tried,new ones have not been put to any test as yet.Thus the old friends are really genuine,otherwise they would have ceased to be friends;so they are as valuable as gold.But this cannot be said about the new friends,for they have not yet been required to undergo the same tests as the old ones.So their worth as friends cannot be claimed to be equal to that of the proven friends.Herein lies the significance of keeping the old friends who have been tried and found real and sincere.It is,of course,advisable to make new friends;but they must not be allowed to replace the old ones.
