Shaykh Ubayd Al-Jaabiree said, “The first angle regarding testing is [that it is done in the following cases]:
- someone whose position needs to be known [whether they are Salafi or an innovator],
- or someone who is basically unknown [and]
- a person who comes into the ranks of Ahlu Sunnah and you need to know something about him [as he may wish teach the people of the Sunnah or translate books for them or marry there daughters for example]…He can be tested so that his affair is known.
The proof for this is what is found in Saheeh Muslim, reported by Mu’aawiyah ibn al-Hakam as-Sulamee, may Allaah be pleased with him. He had a slave-girl that used to keep watch over his sheep. So a wolf came and ate one of the sheep. So when he came and his slave-girl informed him of what happened, he became angry and slapped her in her face. Then he felt remorse about it, so he went to the Prophet (sallallaahu ‘alayhe wa sallam) and told him what happened between them. He noticed that the Prophet (sallallaahu ‘alayhe wa sallam) was disturbed, so he said, “O Messenger of Allaah! I own a slave (other than her), shall I not free him?” He wanted to offer an expiation for his mistake, may Allaah be pleased with him.
I ask Allaah, the Generous, the Lord of the Mighty Throne, to make me and you among them in this life and in the Hereafter, upon the firm statement.
So the Prophet (sallallaahu ‘alayhe wa sallam) said:
“Bring her to me and I will see if she is a believer.”
This is since she was a shepherd, and they are predominantly people who have not submitted to Islaam, or people who do not understand the Religion in its true sense. So he brought her to the Messenger of Allaah (sallallaahu ‘alayhe wa sallam). He said to her:
“Where is Allaah?”
She said, “Above the sky.” He then said to her:
“And who am I?”
She said, “You are the Messenger of Allaah.” 
And in some of the versions of the hadeeth, when he asked her about Allaah, she gestured towards the sky, since she was an Ajamiyyah (a non-Arab), and when he asked her about himself, she gestured towards him and then towards the sky, as if to say, “You are the Messenger of the One above the sky.”
So this hadeeth makes known, dear Muslims, the methodology of the Truth that was found among the Salaf. Perhaps I can phrase that better by saying: It proves clearly how much attention the Salaf paid to ‘Aqeedah (beliefs), that they used to teach the people, even the shepherds. In this case, a slave-girl, a shepherd, was not left to be ignorant, rather her master taught her the pure, correct ‘Aqeedah of Tawheed.
And today we find those who say, “We are in the land of Tahweed [Saudi Arabia] and the Muslims are people of Tawheed, so there is no need to teach Tawheed.” With this, you find people who say that Allaah is everywhere. This is something we are being tried with. You can ask some people who are from the people on the grounds of the two Harams (the two sanctuaries, Makkah and al-Madeenah), they may even live among the people of Tawheed and Sunnah around one of the two Harams, ask them about Allaah and you will find them saying, “Allaah is everywhere, on mountains and in trees, everywhere.”
Maa shaa’ Allaah. Heedlessness about the affairs of ‘Aqeedah.
Secondly, this hadeeth shows that a person whose affair is not clear may be tested so that his affair is made clear to the people.
Likewise, when tribulations have spread, and everything is in a state of chaos, and the people of the Sunnah fear that some may come into their ranks who are not truly people of the Sunnah like them, then they may test the people (and judge them) by their actions and statements, so that their affair becomes known.
The second affair, or the second angle, is that the imtihaan (test) is to revolve around the people of virtue and taqwaa. This is the case when tribulations spread, the storms of innovation rage through the people, causing rifts and openings for evil people to enter among the people of Islaam, so thus they slip in, people who plot against Ahlus-Sunnah with serious plots, and plan strategically against them.
They may be given an imtihaan, they may be asked about the most virtuous of the people, the most pious of the scholars. This is based on what has been narrated from the Salaf, that they used to say, “Test the people of al-Madeenah by (asking them about) Maalik. And test the people of Egypt by (asking them about) al-Layth ibn Sa’d. And test the people of Shaam by (asking them about) al-Awzaa’ee. And test the people of Mawsil by (asking them about) Mu’aafaa ibn ‘Imraan.” 
What is intended is that these people’s affairs will become clear when their positions on the scholars are made known. So whoever shows respect for the scholars, speaks well of them, and displays love for them, then he deserves to be drawn close and honored. And if he speaks ill of them, talks against them, and degrades them, then he is to be repelled.
This was (established) long ago. As for the people of innovation, then they are not to be the subject of an imtihaan (the people are not tested by them). Their opposition to the Sunnah is to be clarified, and the people are not to be tested regarding them. 
 Saheeh Muslim (#1199), the Prophet (sallallaahu ‘alayhe wa sallam) said upon hearing her answers:
“Free her, for verily she is a believer.”
 For similar statements, refer to point #144 of al-Barbahaaree’s Explanation of the Creed (Sharh as-Sunnah).
 Take note that making a person of innovation into an imtihaan and testing the people with him is one thing, and warning the people against him is another. It can not be understood from Shaykh ‘Ubayd’s words that we must be silent about the people of innovation and not warn the people against them.
Ref: Bakkah.net from a published recording entitled Sharh Kitaab al-Eemaan min Saheeh al-Bukhaaree, from the Summer of 1424.
Posted By Abdul Kareem Ibn Ozzie