Deuteronomy 20:3
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; 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;
Deuteronomy 20:3 is part of Moses's rehearsal of the laws and instruction given to Israel before they crossed the Jordan into the promised land. It belongs to his continued recounting of Israel's experiences and God's guidance, which is one constant appeal to serve the Lord, to turn away from the sins that wrecked the other nations, and to exemplify Him, in which alone lay Israel's greatness and continuance, while wonderfully developing the precepts of the law with God's gracious promises. With its surrounding verses it gives the Lord's promise to fight Israel's battles for them in the great campaign against the inhabitants of Canaan if they would be faithful to Him, teaching them faith in God, dependence on Him for success, and His first claim on all gained in the campaign, as shown when Jericho as the firstfruits of that campaign was devoted to Him by His special order.
The verse orders Israel when approaching battle against enemies not to let their hearts faint, not to fear, not to tremble, and not to be terrified because of them. It is linked to sending every fearful and faint-hearted man back to his house, because cowardice in the presence of the enemy is contagious and will make the hearts of his brethren faint as well, while a few courageous men are more effective than a host of cowards. Christian courage under trials is a mark of Christian character. This same rule applies in going to battle in the Lord's cause.