In Parshat Emor (Vayikra 23:10) we learn about the Mitzvah of the Omer:

When you shall enter the Land that I give you and you reap its harvest, you shall bring an Omer from your first harvest to the kohen…

Before any grain produce of the new crop may be eaten, an Omer, the tenth part of an Epha, a measure of ground barley (containing the volume of 43.2 eggs) must be brought to the Beit HaMikdash on the second day of Pesach as an offering showing that we appreciate the fact that the produce of the Land is a gift from God.

Alshich (1508-1600) explains:

There is nothing that profanes and makes a man's heart haughty like great bounty; as it is stated in Dvarim 32:15, “So Yeshurun grew fat and kicked.” They forget God and say that it is “their strength and their might that produced all of this glory for them.” Ingratitude removes them from the good path and from walking after God, to the point that they are soon lost.

Therefore, God, who wishes for our good like a father for a child, loves us and teaches us proper ethics: From the time when the scythe begins to cut the crop of barley - which is the first of the land’s produce - before our hearts become haughty when we see the abundance of produce in the house and in the field, when the threshing floors are filled with grain and the barns with plenty; God comes to open blinded eyes to teach them knowledge.

Before any enjoyment from the bounty of the field comes to their mouth, and before they taste the smallest bit of bread or parched grain, all of the Jewish people bring the first of their harvest to the kohen while saying to Him, may He be blessed, “Behold we recognize that all of the land and everything in it is Yours; and what is Yours from the beginning of it all has been given to You before we eat from anything, to show that everything is from You and that we are not brazen-faced ingrates.” 

And this is the meaning of its statement, “When you come to the land” which you did not need to take with the might of your hands but rather as one who comes to an inheritance: It should not enter your heart to say, “The land was given to us an inheritance from our forefathers and it is ours and our children's forever; and that which we eat its goodness and its produce, it is the effort of our hands that we eat, as we work the land by plowing and reaping and doing all the work in the field until the produce arrives. As none of us stops from work - whether by sowing, planting trees, planting shoots, winnowing, separating - so we eat the bread of the land by the sweat of our brow...”

Therefore, God preceded us by saying, Observe and see that after your coming to the land is not an inheritance or present that has no break but rather “which I give” - in the present tense - and the giving is never completely final. For whenever you turn away from Me, I shall transfer it to others besides you. And you should not let it enter your minds that it is your harvest that you are harvesting, but rather, “you shall harvest the harvest of the land, for it is blessed, and you shall be blessed from its blessing.”

The Land of Israel is a gift that God renews every single day. The Omer helps us take a step back to appreciate the Land and God’s gifts to us. We just concluded the celebration of Yom HaAtzmaut and we are now gearing up for Yom Yerushalayim. It is not a coincidence that both of these holidays are celebrated during the counting of the Omer, the time that we must step back and appreciate the precious gift which is Israel.