Deuteronomy 20:8

Yet more shall the officers speak to the people, and say, Who is the man who is afraid on account of his sin and whose heart is broken? let him go and return to his house, that his brethren be not implicated in his sins, and their heart be broken like his.

cowardly afraid to kill another.

faint hearted afraid to be killed by another.

The Hebrew preposition et before the word the heart seems to be extraneous; as I have explained, however [comment on Exodus 10: 8], it indicates the most important noun in a clause.

AND THE OFFICERS SHALL SPEAK FURTHER UNTO THE PEOPLE, AND THEY SHALL SAY: ‘WHAT MAN IS THERE THAT IS FEARFUL.’ According to the opinion of Rabbi Yosei the Galilean [who says, the fearful is someone who is afraid that he will fall in battle as punishment for his transgressions], after the priest had assured them that G-d would help them and that not one man of them will be lacking, it was fitting that the righteous put their trust in Him, [that He will help them not to be overthrown in battle]. Then, the officers warn those that are afraid [to go into battle] because of the transgressions they had committed. The Torah, therefore, gave everyone the opportunity of attributing his return home because of his house, his vineyard, or his wife, in order to serve as a pretext for others who are returning home because they are afraid of their transgressions. And the meaning of the expression lest he die in the battle [mentioned in each of the three categories] is that he will think so in his heart and he will flee [despite the fact that the priest had already assured them that no one would be lacking after the battle]. But in the opinion of the Rabbi Akiba [who says that fearful is he who cannot endure a pitched battle or bear to see a drawn sword,] the verse is to be understood in its simple meaning, that whoever is still afraid after the assurance of the priest, does not trust in G-d properly and the miracle [of being saved] will not be done for him [and therefore the Torah gave him the opportunity to return home].

ילך וישוב לביתו. If he is afraid that his mazzal is poor

and he would die in battle, seeing that G’d made him worry that he might not live to consecrate his new home, wed his bride, or eat from the fruit of his vineyard, he had assumed that if he was now required to participate in this war it was apparently ordained to prevent him for realising his objectives on earth.
The Torah selected three examples of what would inspire such fear, concern over one’s house, one’s wife, and one’s vineyard. Having first named these specific concerns and declared them as legitimate under the circumstances, the Torah proceeds to include all other kinds of concerns which inspire fear for his impending death in the heart of a person. (verse 8). This pattern is not as unusual as it strikes us at first glance, seeing that Solomon employs it in Kohelet 1,3-9. He begins by listing examples of things he considers futile in this life, such as 1) a generation goes, another takes its place, a constant change, nothing remaining whereas the “dead” earth remains forever.
2) The sun rises and the suns sets; 3) the rivers all end up in the ocean but the ocean never flows over. Solomon tires of listing all the phenomena that recur constantly since the days of creation, all except man, because no new generation is exactly like the generation preceding it. The result is that the generation that has died is not remembered as it has never been replaced. This is why Solomon considers death the most futile phenomenon, seeing it wipes out what there was without replacing it. By the time Solomon reaches verse 9 he comes to the conclusion that seeing that there is nothing new in this life on earth which has not happened before, everything is remembered by reason of that very fact. However, just because one generation is not at all like a previous generation, man’s existence is apt to be forgotten, precisely because there is no one around anymore to duplicate what previous generations have done. There is therefore nothing by which to remember the existence of previous generations. (verse 11 there)