(be) "on guard..." (shomer)...

Exo 23:20 Behold, I am about to send a messenger before you, to guard you in the way, and to bring you to the place which I have prepared.

Exo 23:21 Be on guard before Him, and listen to His voice. Do not be rebellious against Him, for He will not forgive your transgressions; for My name is in Him.

Exo 23:22 For if you fully listen to His voice, and do all which I speak, I will be an enemy to your enemies, and will be a foe to your foes.

(Deu 2:4)  And command the people, saying, You are passing over into the border of your brothers, the sons of Esau, who live in Seir, and they shall be afraid of you. And you shall be on guard very much;

Deu 2:5 you shall not fight against them, for I will not give their land to you, even to a step of a sole of a foot, for I have given Mount Seir to Esau as a possession.

Deu 2:6 You shall buy food from them with silver, and you shall eat; and you shall buy water from them with silver, and you shall drink.

Deu 2:7 For YAHWEH your Elohim has blessed you with all the work of your hands; He has known your walking through this great wilderness. YAHWEH your Elohim has been with you these forty years; you have lacked nothing.

(Deu 4:9)  Only, be on guard for yourself and keep your soul carefully, that you do not forget the things which your eyes have seen; and that they not depart from your heart all the days of your life. And you shall make them known to your sons, and to your sons' sons.

(Deu 4:15)  Therefore you shall carefully be on guard for your souls, for you have not seen any likeness in the day YAHWEH spoke to you in Horeb out of the midst of the fire,

Deu 4:16 lest you act corruptly, and make for yourselves a carved image, a likeness of any figure, the shape of a male or female,

Deu 4:17 the shape of any animal in the earth; the shape of any winged bird that flies in the heavens;

Deu 4:18 the shape of any creeping thing on the ground; the shape of any fish in the waters under the earth;

Deu 4:19 and that you not lift up your eyes towards the heavens and shall see the sun, and the moon and the stars, all the host of the heavens, and you be drawn away and worship them, and serve them; which YAHWEH your Elohim has allotted to all the peoples under all the heavens.

Deu 4:20 And YAHWEH has taken you, and has brought you forth out of the iron furnace, out of Egypt, to be a people to Him, an inheritance, as it is this day.

(Deu 4:23)  Be on guard for yourselves, that you not forget the covenant of YAHWEH your Elohim, which He has made with you, and make to yourselves a graven image, a likeness of anything which YAHWEH your Elohim has forbidden you.

Deu 4:24 For YAHWEH your Elohim is a consuming fire; He is a jealous El.

(Deu 5:1)  And Moses called to all Israel and said to them, Hear, Israel, the statutes and the judgments which I speak in your ears today. And you shall learn them, and be on guard to do them.

Deu 6:10 And it shall be, when YAHWEH your Elohim shall bring you into the land which He has sworn to your fathers, to Abraham, to Isaac, and to Jacob, to give to you great and good cities, which you have not built,

Deu 6:11 and houses full of every good thing which you have not filled, and wells dug which you did not dig, vineyards and olive yards which you did not plant; and you shall eat and be satisfied;

Deu 6:12 then you shall be on guard that you do not forget YAHWEH who brought you out of the land of Egypt, out of the house of slaves.

Deu 6:13 You shall fear YAHWEH your Elohim, and you shall serve Him, and you shall swear by His name.

(Deu 24:8)  Be on guard in the plague of leprosy, that you watch closely and do according to all that the Levitical priests shall teach you. As I commanded them, so you shall be careful to do.

(Jos 1:8)  This book of the Torah shall not depart out of your mouth, and you shall meditate on it by day and by night, so that you shall be on guard to do according to all that is written in it. For then you shall prosper your way, and then you shall act wisely.

H8104

שׁמר shâmar shaw-mar' A primitive root; properly to hedge about (as with thorns), that is, guard; generally to protect, attend to, etc.: - beware, be circumspect, take heed (to self), keep (-er, self), mark, look narrowly, observe, preserve, regard, reserve, save (self), sure, (that lay) wait (for), watch (-man).