It is characteristic of ...

It is characteristic of spontaneous friendship to take on first, without enquiry and almost at first sight, the unseen doings and unspoken sentiments of our friends; the parts known give us evidence enough that the unknown parts cannot be much amiss.
It is characteristic of spontaneous friendship to take on first, without enquiry and almost at first sight, the unseen doings and unspoken sentiments of our friends; the parts known give us evidence enough that the unknown parts cannot be much amiss.