Ben Azai: The pasuk states (Koheles 10, 1), "Dead flies spoil the oil of the perfumer'' - even one dead fly spoils the oil of the perfumer; so too a person who makes one sin can lose all of the merit in his hands.

R. Akiva: The pasuk states (Yishayahu 5, 14), "The netherworld has increased its appetite and opened wide its mouth without limit'' - the pasuk says "limit'' rather than "limits'' - to a person who does not have even one Mitzvah in his hand to help him on the side of merit.

This is referring to the judgment in the next world, but in this world, even if there are 999 angels prosecuting and one angel defending him, Hash-m tips the person to the side of merit.

What is the source for this? The pesukim state (Iyov 33, 23-24), "If there will be for him even one defending angel out of a thousand to tell of a man's straightness, then (Hash-m) will be gracious to him and say - Redeem him from descending to the grave, I have found atonement''.

R. Yochanan: If you hear something from R. Eliezer son of R. Yosi Haglili, pierce your ear like the hole of a millstone (that allows in a lot, but lets out a little) and listen to it.

As he said...Even if 999 angels are prosecuting and one angel is defending him, Hash-m tips the person to the side of merit.

And it is not only if that one angel is entirely defending him, but even if 999 aspects of that angel are prosecuting him and there is only one aspect of that angel that is defending him, Hash-m tips the person to the side of merit.

What is the source for this? The pasuk does not say, "If there will be for him even one from a thousand'', but rather, "...even one out of a thousand'' - i.e. one aspect from a thousand aspects of the same angel.

The pasuk said after that, "...then (Hash-m) will be gracious to him and say - (lit.) Redeem him from descending to the grave, I have found atonement'' - (those words are more correctly translated as "afflict him'') - Hash-m has found him atonement to save him from affliction.

This was said in reference to this world, but in the next world, one who has mostly merit will go to the Garden of Eden; one who has mostly liability will go to Gehinom.