Gemara: There is a disagreement among the Tannaim as to what failing the sons of Eli were guilty of. Rabbi Meir says: The portion they had coming to them as Levi’im they requested
"with their mouths." Rabbi Yehuda says: They gave the people the responsibility of making money for them. Rabbi Akiva said: They forcefully took a greater share of tithes than usual. Rabbi Yossi says: They took gifts [there are different opinions as to which gifts and whether they had any rights in them] by force.
Ein Ayah: The moral failings that begin to afflict someone who has influence and is involved in a position of public service, begin by degree, as is true for other moral failings. It is a very dangerous decline and "jumps" in strange ways because there are broad areas of moral challenge just as a leader’s power spreads over a broad area.
Under proper circumstances, the moral purity of a leader, especially one who serves on spiritual matters, should reach the level whereby he will not demand even the benefits a leader deserves. This is a sign that he sees his public service as so important that he does not deserve any reward for it and that he should relinquish his rights for the honor of serving in such a lofty post in the "palace of the King of the Universe," especially when involved in work of justice for the masses. If one feels comfortable demanding money, it shows that his spirit has darkened to the point that he does not feel the great value of public work and that the very involvement in such lofty matters is the greatest reward.
Once a leader leaves an approach of light, a sin drags along another sin. Not only will he no longer view himself as not deserving reward, but he will view his tasks as toilsome. Then he will feel that since he is toiling for the public’s benefit, members of the public are responsible to toil to make money for him, as Rabbi Yehuda said.
From that point, he is just one step from general corruption. One who is involved in matters of justice but does not see anything special about that can be corrupt both quantitatively and qualitatively in disregard of moral responsibility. As a rule, when one is in a position that demands extra morality and sanctity and he does not elevate himself, he will lose even his previous moderate level. Involvement in justice should improve a person, making him like a partner in the creation of the world (see Shabbat 10a). When he refuses to recognize this and work diligently to succeed in his holy task, his tendency toward lowliness and his dangerous overfamiliarity with the field of justice will bring him to seek improper external honor. Quantitatively, he may take more tithes than he deserves and qualitatively he may acquire them through improper force.
It is only partially bad when he has certain rights to the thing that he seeks. If he deteriorates further, he is liable to retain only an empty connection to the world of justice, where it is just a matter of external process, and he will lack any internal desire to act justly. Then he may take "presents by force," which is a contradiction in terms. If it is taken by force, it is not a present. This is a sign of actions which he calls "justice" but share nothing positive with it. He will not even be careful to have any way to rationalize to himself why he has rights to that which he is taking.
All of these stages of deterioration start to afflict one who looks at a judicial role as an opportunity for betza (which can mean looking for profits or even looking for bribes). This is instead of looking at the opportunity to settle disputes between people as a divine-like activity, as "charity and justice are the foundation of His throne" (Tehillim 97:2).