1 When thou goest out to battle against thine enemies, and seest horses, and chariots, and a people more than thou, be not afraid of them: for Yahweh thy Elohim is with thee, which brought thee up out of the land of Egypt.

2 And it shall be, when ye are come nigh unto the battle, that the priest shall approach and speak unto the people,

3 And shall say unto them, Hear, O Israel, ye approach this day unto battle against your enemies: let not your hearts faint, fear not, and do not tremble, neither be ye terrified because of them;

We all know that life in the Truth is a battle.

I do not mean a battle with errors in others, but with unbelief in ourselves; by unbelief I do not mean an unbelief that we would affirm or own to, but the latent unbelief that belongs by nature to the unenlightened human brain on every subject - the passive feeling that belongs to ignorance.

We are all ignorant at the start - ignorant of everything. Knowledge comes slowly from without. It has to be "sought for" as the Scriptures represent: and when found, it won't stay unless we take means to retain it.

Human memory is weak, and soon forgets, - especially with regard to the class of things that constitute the Truth. They are all things "not seen," whether past, present or future; and some of them are things for which we have not much natural liking and therefore forgetfulness and consequent unbelief becomes very easy, unless we are on our guard.

Bro Roberts - Regarding God, and his works

4 For Yahweh your Elohim is he that goeth with you, to fight for you against your enemies, to save you.

5 And the shoterim shall speak unto the people, saying, What ish is there that hath built a bais chadash, and hath not dedicated it? Let him go and return to his bais, lest he die in the milchamah, and another ish dedicate it.

5 And the officers shall speak unto the people, saying, What man is there that hath built a new house, and hath not dedicated it? let him go and return to his house, lest he die in the battle, and another man dedicate it.

6 And what man is he that hath planted a vineyard, and hath not yet eaten of it? let him also go and return unto his house, lest he die in the battle, and another man eat of it.

7 And what man is there that hath betrothed a wife, and hath not taken her? let him go and return unto his house, lest he die in the battle, and another man take her.

8 And the officers shall speak further unto the people, and they shall say, What man is there that is fearful and fainthearted? let him go and return unto his house, lest his brethren's heart faint as well as his heart.

9 And it shall be, when the officers have made an end of speaking unto the people, that they shall make captains of the armies to lead the people.

10 When thou comest nigh unto a city to fight against it, then proclaim peace unto it.

11 And it shall be, if it make thee answer of peace, and open unto thee, then it shall be, that all the people that is found therein shall be tributaries unto thee, and they shall serve thee.

12 And if it will make no peace with thee, but will make war against thee, then thou shalt besiege it:

13 And when Yahweh thy Elohim hath delivered it into thine hands, thou shalt smite every male thereof with the edge of the sword:

14 But the women, and the little ones, and the cattle, and all that is in the city, even all the spoil thereof, shalt thou take unto thyself; and thou shalt eat the spoil of thine enemies, which Yahweh thy Elohim hath given thee.

15 Thus shalt thou do unto all the cities which are very far off from thee, which are not of the cities of these nations.

16 But of the cities of these people, which Yahweh thy Elohim doth give thee for an inheritance, thou shalt save alive nothing that breatheth:

17 But thou shalt utterly destroy them; namely, the Hittites, and the Amorites, the Canaanites, and the Perizzites, the Hivites, and the Jebusites; as Yahweh thy Elohim hath commanded thee:

18 That they teach you not to do after all their abominations, which they have done unto their god's; so should ye sin against Yahweh your Elohim.

Duty is obedience to the commandments of God, and not the following of a supposed natural bias. Natural bias may be whim and darkness. The keeping of the commandments of God is the following of the light, whatever the commandments are.

He makes alive, and has a right to kill, and when he says "Kill ", it is wickedness to refrain. The slaughter of the wicked Canaanites was by the order of God, and became an act of righteousness. So with all the other so-called "difficulties". They are difficulties that vanish with a right understanding.

Law of Moses Ch 3

19 When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof by forcing an axe against them: for thou mayest eat of them, and thou shalt not cut them down (for the tree of the field is man's life) to employ them in the siege:

20 Only the trees which thou knowest that they be not trees for meat, thou shalt destroy and cut them down; and thou shalt build bulwarks against the city that maketh war with thee, until it be subdued.