מדרש אויף דברים 14:1

We are taught in a Baraitha, R. Maier says: "If a common questioner discusses, 'If your God likes the poor, why then does He not sustain them?' answer him, 'for the purpose of saving us [through the charity] from the punishment of Gehenna.'" The same question did Tarnusruphus ask of R. Akiba: "If your God likes the poor, why then does he not sustain them?" And R. Akiba answered him: "For the purpose of saving us [through the charity] from the punishment of Gehenna." To which Tarnusruphus rejoined: "On the contrary, for this you deserve to be punished with Gehenna; and I will give you a parable from which you will understand why. A frail king who became angry at his slave and put him in prison, announced his desire that nobody should give him either food or drink. In spite of this, a person fed him and gave him drink. When the king becomes aware of it, would the king not be angry at that man? And ye Israelites are called servants, as it is written (Lev. 25, 55) For unto Me are the children of Israel servants." R. Akiba answered: "I will give you another parable, to which my previous answer is to be compared: A frail king became angry with his son, put him in prison, and commanded that nobody should give him either food or drink; in spite of this command, a man fed him and gave him drink. When the king became aware of it, would he not be grateful to this person and even send him a present? And we Israelites are called children, as it is said (Deut. 14, 1) Ye are the children of the Lord," etc. Tarnusruphus, however, said: "You are named children and also servants; i.e., children, when you are doing the Omnipotent's will, and servants when you act against the Omnipotent's will. And you will admit, that now you are acting against His will [since your Temple is destroyed and you are in exile].." R. Akiba answered: "With regard to this, the passage says (Is. 58, 10) Is it not to distribute thy bread to the hungry and the afflicted souls with the members of thy house. The afflicted souls [you will admit] refer to us in our present circumstances, and nevertheless, it says there, Is it not to distribute thy bread to the hungry?"

Another matter, “each at his banner,” that is what is written: “He would find him in a land of wilderness…” (Deuteronomy 32:10); the Holy One blessed be He found a great finding in Israel, as it is stated: “Like grapes in the wilderness I found Israel” (Hosea 9:10); “He would find him in a land of wilderness,” the world was a wilderness until Israel departed from Egypt. “And in an empty, howling wasteland” (Deuteronomy 32:10); the world was emptiness and wailing. Until Israel departed from Egypt, and until they received the Torah, He did not do so.⁶Did not redeem the world, which was a wilderness. But when they departed from Egypt and received the Torah, what does [the verse] say? “He would encircle him, He would grant him understanding, [He would preserve them like the pupil of His eye]” (Deuteronomy 32:10). “He would encircle him,” that he surrounded them with clouds of glory. “He would grant him understanding,” that He caused them to understand the Torah. “He would preserve them,” happy are the ears that heard. To what extent did He love them, protect them, and preserve them? It was, as it were, to the extent of the pupil of his eye. See how He loved them, how He protected them, and how He preserved them, as God said to Moses: ‘Moses, say to them that they should craft a Tabernacle in their midst. As it were, I am leaving the supernal and descending and resting in their midst.’ Moreover, He arranged them according to banners in His name. The Holy One blessed be He said to Moses: ‘Arrange them according to banners in My name. Why? It is because they are My children, as it is stated: “You are children to the Lord your God” (Deuteronomy 14:1). And they are My hosts, and likewise it says: “I will take out My hosts, My people the children of Israel, from the land of Egypt” (Exodus 7:4). And likewise it says: “The banner of the camp of Judah, according to their hosts” (Numbers 2:3). Because they are My hosts, I will arrange them according to banners in My name.’ That is what is written: “Each at his banner.”

2) "upon their head": What is the intent of this? Because it is written (Devarim 14:1) "Do not lacerate yourselves and do not make baldness between your eyes for the dead," I might think that only "between the eyes" entails liability. Whence is the head included? From "upon their head," to include (all of) the head.