How should we choose our friends according to Islam?

We should choose the friend that believes in and abide by our
religion(Islam) and gives great respect to what Allah (SWT) and
Prophet Muhammad (saw) had ordered us. And we should stay away from
the one who is not well mannered and gives no attention to what Islam
isabout or what pleases or displeases Allah (SWT), for he will surely
affect usnegatively. There is no good if the companion drowns us in
sins and displeasing Allah (SWT). The bases for the actions of those
who follow the evil ways are corrupt; their actions are built upon
misguidance and deviation.
Good friends are those who share with their companions both happiness
and sadness. Ifwe share our feelings with the wrongdoers whose actions
are worthless and based on corruption, then we are following the same
ways and standards as they aredoing, and we will end up being as
corrupt as they are, and then we are in a big trouble, how can we face
Allah's (SWT) dissatisfaction and displeasure? Instead of making
friends with the misguided ones we should befriend the righteous, yet
treat the rest in a gracious and justmanner. Staying at sufficient
distance is necessary; yet treating everybody in a noble andkind
manner is required.
The danger of having corrupt friends isn't confined to the worldly
life. Such friendships produce repentance on the Day of Resurrection,
too!
Allah (SWT) , the Exalted says in the Noble Qur'an:"And (remember) the
daywhen the unjust one shall bite his hands saying: O! Would that I
had taken a way with theMessenger! O woe is me! Would that I had not
taken such a one for a friend! Certainly he led me astray from the
reminder after it had come to me;" (Surah Al-Furqan, 25:27-29)
The two main regrets on the day of judgement are(1) Not following
ProphetMuhammad (saw) on the path of guidance and (2) Befriending a
person who diverted one from the truth.
Imam Ali ibn Abi Talib (as)has said: "The felicity of this and the
next world lie in two things: firstly, keeping secrets; and secondly,
friendship withthe good. And the miseries of this and the next world
are summed up in two things: firstly, divulging secrets; and secondly,
friendship withwicked persons."
So take heed before the inevitable day of judgement comes and we are
reckoned for our acts.
Allah (SWT), the Exalted says in the Noble Qur'an:"Friends on that Day
will be enemies one to another, except al-Muttaqun (i.e. those who
have Taqwa/Piety)."(Surah Az-Zukhruf, 43:67)
It is wise to choose moderation in dealing with friends. Excessive
love and confidence in friends are unacceptable since it happens that
a friend may change into an enemy and use the secrets that he had
shown as weapons.
Allah (SWT), the Exalted says in the Noble Qur'an:"And cooperate in
righteousness and piety, but do not cooperate in sin and aggression."
(Surah Al-Maeda, 5:2)
Imam Ali ibn Abi Talib (as)said: "When you cherish someone you should
cherish him moderately for he may be your enemy someday, and when you
hate someone you should hate him moderately for he may be your friend
someday."Also said: "If you intend to cut yourself off from a friend,
leave some scope for him from your side bywhich he may resume
friendship if it so occurs to him some day."
Imam Jafar Sadiq (as) said: "The secrets that you must show before
your friends are only those through which your enemies cannot harm
you, for a friend may change into an enemy."