“The scholars of Hadith are broken up into different categories in regards to al-Jarh wa at-Ta’deel. From them are those who are: lenient, strict, and moderate”
The Shaykh Muhammad ibn Saalih al-’Uthaymeen (may Allah have mercy on him) mentioned this point of benefit in his explanation of the great science of hadith poem entitled, “al-Bayquniyyah”. His comments can be found under the fourth line of the poem which reads:
يرويه عدل ضابط عن مثله … معتمد في ضبطه و نقله
One who is upright and precise, narrates from his like,
Reliable in his precision, as well as his transmission
“It is known that some scholars of hadith were harsh in regards to praising (Ta’deel), and some of them were lenient. (Also) some of them where harsh in criticizing (Jarh) when there was nothing to criticize.
And there were scholars who were the opposite and were too lenient and praised someone when that person was not deserving of praise. And this is something known with the people of knowledge.
So whoever is severe with his narrators then his praise (for someone) will be closer to be accepted than the scholar who is lenient. However the correct/right (position) is that mankind should be fair and not too harsh or lenient. Because if we were to be too harsh then perhaps he would reject an authentic hadith about the Prophet (peace be upon him). Likewise, if a man were to be too lenient then perhaps he may attribute a hadith to the Prophet (peace be upon him) while not be correctly affirmed to him.”