a friend in need is a friend indeed

/ə ˌfɹɛnd ɪn ˈniːd ɪz ə ˌfɹɛnd ɪnˈdiːd/proverb
Graduate
1

If a friend helps one when one is in need, that person is a true friend.

2

If a friend is in need of help, it is beneficial and wise to help them.