Friends, are people that will help you during difficult times, they will listen to you, support you, motivate you, tell you when you are wrong and expect you to do the same in return.
A friendship is not a one way relationship. It’s a
two ways relationship.
Friends can be a lot of things:
Your confident
Your family
Your lover
Your coach, motivation and/or inspiration
As you mention in your post, here is Arabic proverb related to it
"مودة الصديق تظهر وقت الضيق"
The right friend when we in the difficult time