Tafsir of Al-Ma'idah 5:21

(O my people, enter the Holy Land) The call is repeated with the addition of honorific attribution, emphasizing the importance of the matter and exaggerating the urging for them to comply with it. The "Holy Land," as reported from Ibn Abbas (may Allah be pleased with both of them), as-Suddi, and Ibn Zayd, is Bayt al-Maqdis (Jerusalem). Al-Zajjaj said: It is Damascus, Palestine, and Jordan. Mujahid said: It is the land of Mount Tur and its surroundings. From Mu'adh ibn Jabal, it is what lies between the Euphrates and the Arish of Egypt. "Sacredness" (Taqdis) means purification. That land was described as such either because it is purified from polytheism, as it was made the dwelling place of the Prophets (peace and blessings be upon them), or because it is purified from calamities, and the dominance of the tyrants over it does not negate its sacredness, or because it was purified from drought and hunger. It is also said: It was named "holy" because it contains the place where one is purified from sins.

(Which Allah has ordained for you) meaning: He decreed it and apportioned it for you, or it was written in the Preserved Tablet that it would be your dwelling place. It is reported that Allah the Exalted commanded the Friend (Khalil - Abraham), peace and blessings be upon him, to ascend Mount Lebanon, and whatever his sight reached was for him and his descendants; thus, that land was the extent of his sight. According to Qatadah and as-Suddi, the meaning is: which Allah commanded you to enter and made obligatory upon you. "Writing" (Kitab) here is like His saying, the Exalted: "Fasting is ordained (kutiba) for you." Many exegetes have inclined toward the first two possibilities. On the first, "writing" is figurative, and on the second, it is literal. They qualified it with: provided you believe and obey, due to His saying to them after they disobeyed: "Then it is forbidden to them."

(And do not turn back [on your heels], for then you will become losers) The consequence of disappointment and loss upon turning back indicates that the "ordainment" is conditioned upon the struggle resulting from faith, definitively. "Heels" (Adbar) is the plural of "dabar," which is the places behind them, such as Egypt and others. The prepositional phrase serves as a state (hal) for the subject of "turn back," meaning: do not retreat from your destination, turning back out of fear of the tyrants. It is also permitted that it relates to the verb itself. It is possible that "turning back" signifies turning their hearts away from the belief they held, a non-sensory turning—meaning: do not regress from your religion through disobedience and lack of trust in Allah the Exalted. Abu Ali al-Jubba'i inclined to this.

His saying, the Exalted: (for then you will become losers) is either jussive by way of conjunction, which is the most apparent, or accusative as the response to the prohibition. Al-Shihab said: It is of the category of "Do not disbelieve, [lest] you enter the Fire," though this is contested, contrary to al-Kisa'i, and there is a view on this which is not hidden. The intended meaning of "loss" is the loss of both abodes.