However, if it refers back to two specific friends who have already been mentioned in the passage, then it may well make perfect sense.
I am out shopping with two friends when I decide that I want to steal a pair of trousers from my favourite shop. I can't do it alone though. Surprisingly, my two friends are willing to help me.
It is clear which two friends you are referring to, because they have been mentioned in the first sentence.
Student or Learner