explain the belief of the covenant and the promise land.?

Jesus fulfilled the old law ten commandments (old covenant) and ushered in a new covenant ( Hebrews 10:16-18) where your sins and lawless acts I will remember no more and where these have been take away there is no longer any sacrifice for sin.

Abraham, assuming he existed, would have been considered a pagan because he believed in multiple gods - this according to archeological evidence regarding the society of his era. The earliest bible was written circa 300 BCE, hundreds of years after the events it purports to describe occurred. Very little of it has any support whatsoever from other sources, such as archeological finds or records kept by government agencies of the day.

As far as the "covenant," in theory, God promised a certain part of territory to Abraham's descendants. There again, the people who have the greatest claim to being Abraham's descendants, assuming he lived in the "promise land," would be Palestinian Arabs, seeing as how they have been living in the same locale ever since Abraham's time. Long ago, these descendants of Abraham mostly converted to Christianity (both the Jews and the pagans) and later Islam - well about 10% of them remain Christian to this day. An even tinier number remained Jewish.

As far as the history of the jews in and out of the promised land, there was a Jewish kingdom in the promised land known as Hasmonean kingdom of circa 150 BCE. To keep themselves in power, the king made agreements with the Roman empire, but eventually lost independence as the Romans sent in troops to help the king quell rebellions and bolster his rule. In any case, the Jews of the day (being allies of the Romans) sent missionaries to all corners of the Roman empire and converted a lot of people to Judaism, according to some sources as much as 10% of everyone throughout the Roman empire were Jewish at one time. In the early years of Christianity, it was strictly against the Roman law, unlike Judaism. Well some Jews didn't like the Romans and rebelled but the Romans crushed them. But most Jews didn't have such a problem. Even after the Roman empire fell, Jews continued to send out missionaries. The bulk of eastern European Jewish ancestry is from the kingdom of Khazaria, around whats now southern Russia, which converted to Judaism around the 8-9th century CE. Khazaria was overrun by Mongols and destroyed by the plague later, and in the end Christianity and Islam won the conversion rivalry.

As for the current state of affairs in Palestine, in the late 1900s a group of European Jews known as Zionists decided to create a Jewish state in Palestine (even though they didn't come from there). To do so, they needed to get rid of the the native people of "the promised land" who were no longer Jewish (those that ever had been). At the time, most Jews wanted to stay in their homes in Europe or move to the US, but the rise of the Nazis forced many out - and early on, the Zionists helped them remove Jews from Europe in order to get them to go to Palestine. In 1948 these European Jews conducted a campaign of terror and mass murder, going into villages and making the men surrender, then lining them up and shooting them, sometimes the women and children too. And going around major cities and threatening to do the same. With the majority of non-Jews forced out, the Zionist proclaimed their new state of Israel.

The current state is Israel rules all of historic Palestine, and is still trying to force non-Jews to leave by making life difficult, denying adequate water, housing, movement, access to jobs and keeps taking farmland and homes away from them. Periodically, Israel bombs Gaza, which is a tiny sliver of Palestine inhabited mostly by refugees from what's now Israel. And it allows Jewish settlers to run pogroms against Palestinian Arabs, killing farmers and kids with impunity.