His attitude, always to bear in mind the good of the next person, made him adopt a more lenient attitude in all matters of permitted and forbidden things, based on the principle "the power to rule leniently is to be preferred." As has been stated, Rabbi Israel [Salanter] would punctiliously observe all stringencies and comply with all opinions. This applied where he himself alone was involved. Wherever others were concerned, he would always seek the ways and means to rule leniently. This accounts for his many well-known rulings in matters pertaining to health and danger to life,"danger to life being graver than ritual prohibitions."
From here stemmed his audacious granting of permission to perform acts otherwise forbidden on Shabbat and to eat on Yom Kippur during the outbreak of the cholera epidemic in Vilna. And from here stemmed his lenient ruling on his own conduct where others might thereby suffer hardship. Reliable sources indicate that one of the reasons for Rabbi Israel [Salanter] refusing to accept a rabbinical appointment was that he sided with the more lenient opinions in many halachot in opposition to the prevailing stricter rulings of the other authorities, and he was unwilling to stir up objections and arguments. --The Mussar Movement, Volume 1, Part 2 pages 253-54.
There is another extremely high level of humility – humbling oneself before one's teachers, before the wise and before the righteous who walk in just paths – thinking to oneself: These are the servants of the Blessed One, His bondmen and His lovers, and, because of this, lowering himself before them and honoring them. It is also a good variety of humility if he thinks: I shall humble myself before them so that they will draw me near and teach me and chastise me and lead me in the ways of the Blessed One. – Rabbi Shraga Silverstein, Orchot Tzadikim, The Gate of Humility