Shaykh Muḥammad ibn Hādi al-Madkhalī:

‘Whose affair could [possibly] be hidden after you look at his companion? 

the young man’s nature is indicated by a sign which is apparent on his forehead’ 

Whose affair can be hidden after you look to who is with him? The general folk, nowadays, who do not read or write, if they see you walking with a blameworthy person, they would say to you directly, “Didn’t you find anyone else to walk with?!”  Is that not the case?! Why [would they say such a thing]?! In order to scold you for walking with an individual whom it is degrading for you to accompany.  This was indeed [a norm] among the Salaf – may Allah ﷻ have mercy upon them all. 

Al-Aʿmāsh said: “They [the Salaf] would not [need to] ask about an individual after [considering] three matters” [After (considering) three matters they would not ask about him; if they noticed from him (these) three things]: 1) Whom he accompanies. 2) whom he visits 3) and whom he has close ties with from the people”

Who is he close with?  Who does he walk with? Who does he come and go with? That is it [sufficient]. They know him [by way of this].

As is narrated by Yaḥya Ibn Saʿīd al-Qahtān, the eminent Imām; [who] said: “Sufyān al-Thawrī arrived in Basra – Yaḥya was from Basra and Sufyān was from Kūfa. Yaḥya Ibn Saʿīd al-Qahtān narrates, “When Sufyān al-Thawrī arrived in Basra he began to look into the affair of Rabīʿ ibn Sabeh al-Saʿdi and his status among the people. He [Sufyān] then asked: “What is his creed?” So they replied. “His creed is nothing but Sunnah” So he asked a second question: “Who are his entourage?” They said, “The people of Qadr [Qadariyah sect] so he said: “Then he [Rabīʿ] is Qadarī [i.e. one of them]“.