Genesis 37:22

And Reuben said, Let us not shed innocent blood. Throw him into this pit in the wilderness, but the hand of the slayer stretch not forth against him; because he would deliver him from their hand, and restore him to his father.

SHED NO BLOOD. Reuben said to them: “I would have been tolerant of you when you thought to kill him by your subtle intrigues, for I too hated him and desired that he be killed by others. But do not spill blood with your hands. Far it be from you!” And Reuben’s intent in all this was to rescue him and restore him to his father. Now Scripture relates that which Reuben told them when they paid heed to him. However, originally he told them other things which they did not accept, as he said to them afterwards, Spoke I not unto you, saying: Do not sin against the child and you would not hear? Now when he saw that they would not listen to the extent of releasing him, he said to them, “If so, shed no blood with your own hands.”
Now Reuben did not say, “Shed not his blood,” [but instead, he said, “Shed no blood,”] in order to make it appear that he is not saying it because he loves him, but in order that they should not spill blood. Thus he taught them that the punishment of he who indirectly causes death is not as great as that of he who personally spills blood.
The meaning of the expression, This pit that is in the wilderness, is that this pit is deep and he will not be able to get out of it, and it is in the desert, and if he cries for help there is no one to rescue him as no one passes by there.
Now Scripture relates that the pit was empty and did not contain water. Had there been water in it they would not have drowned him as they had already avoided spilling his blood. Now Rashi writes: “Since it states that the pit was empty, do I not know that there was no water in it? Why then does it say that there was no water in it? It means to state that water indeed was not in it, however it did contain serpents and scorpions.” This is Rashi’s language quoting from the words of our Rabbis. If so, the serpents and scorpions must have been in the cracks of the pit, or it was deep and they did not know about them. Had they seen them and known that they did not harm Joseph, it would have become clear to them that a great miracle had been done to him, and that he was indeed a perfectly righteous man. They would then have known that his merits would save him from all evil, and how would they touch the anointed one of G-d in whom He delights and whom He saves, even as it says, My G-d hath sent His angel, and hath shut the lions’ mouths, and they have not hurt me; for as much as before Him innocency was found in me. But, we must therefore conclude, they did not know anything about it.
In line with the simple meaning of the verse, it states that the pit was empty and completely devoid of water, for even if there were a little water in it, it would still be called “empty.” to indicate that there was no water at all in it. Similarly, For thou shalt die and not live, which means “not live at all, under any circumstances.” Such redundancies are all for the purpose of clarification and emphasis.

השליכו אותו אל הבור הזה אשר במדבר, where no one passes so that he will die from natural causes.

למען הציל, in order to really save him. The verse illustrates Reuven’s intention of not only saving Joseph’s life, but of bringing him back safely to his father, as the Torah testifies later in the course of its narrative.

ויד אל תשלחו בו, according to your judgment that he deserves killing as a רודף, someone threatening you with death or perdition. (compare Samuel I 24,13 מרשעים יצא רשע וידי לא תהיה בך, “although from wicked people come wicked deeds, my hand will never touch you. [David telling G’d that he will personally not harm his persecutor King Sha-ul, but he leaves it to G’d to deal with him. Ed.]

למען הציל אותו, in order to raise him from the pit afterwards.

אל תשפכו דם, his blood is innocent, i.e. he is not guilty of a capital crime. But throw him into this pit if you are so angry about his dreams and the way he presents them. You may repay him by making him feel pain such as yours, but do not touch him in a way that will lead to his death. When Reuven said: “throw him into this pit,” he did so in order to know where to find him later and to bring him back safely to his father after rescuing him from the pit. He did not mean for Joseph to be harmed in any way.