From a Muslim point of view;

God says about the Jews (interpretation of the meaning): “Do you (faithful believers) covet that they will belive in your religion in spite of the fact that a party of them (Jewish rabbis) used to hear the Word of God (the Tawraat), then they used to change it knowingly after they understood it?” [al-Baqarah 2:75]

Qutaadah said (one of the Prophet companions) : “The phrase ‘then they used to change it knowingly after they understood it’ refers to the Jews, who used to hear the words of God, then they altered it after they had understood what it meant.”

Abu ‘Aaliyah said: “They took what God had revealed in their Book describing Muhammad (peace and blessings of God be upon him), and changed its meaning.” Ibn Zayd said: “The phrase ‘[they] used to hear the Word of God (the Tawraat), then they used to change it’ refers to the Torahwhich God revealed to them; they changed it, making what it permitted forbidden, and what was forbidden allowed, changing the truth to falsehood and falsehood to truth…” [Tafseer Ibn Katheer]

God also said (interpretation of the meaning): “Among those who are Jews, there are some who displace words from (their) right places and say: ‘We hear your word (O Muhammad) and disobey,’ and ‘Hear and let you (Muhammad) hear nothing.’ And Raa’ina [in Arabic this means, ‘Be careful, listen to us and we listen to you,’ whereas in Hebrew it means ‘an insult.’] with a twist of their tongues and as a mockery of the religion (Islam). And if only they had said, ‘We hear and obey,’ and ‘Do make us understand,’ it would have been better for them, and more proper, but God has cursed them for their disbelief, so they believe not except for a few.” [al-Nisaa’ 4:46]

The phrase “[they] displace words from (their) right places” means that they misinterpret them and understand them in a way that God did not intend, doing this deliberately and inventing lies against God. [Tafseer Ibn Katheer]

God says (interpretation of the meaning): “So because of their breach of their covenant, We cursed them, and made their hearts grow hard. They change the words from their (right) places and have abandoned a good part of the Message that was sent to them. And you will not cease to discover deceit in them, except a few of them. But forgive them, and overlook (their misdeeds). Verily, God loves al-Muhsineen (good-doers).” [al-Maa’idah 5:13]

The phrase “because of their breach of their covenant, We cursed them” refers to the fact that they broke the Covenant which had been made with them, so God cursed them, i.e., He kept them away from following the True Guidance. “[We] made their hearts grow hard” means that they will not benefit from any preaching because their hearts are so hard. “They change the words from their (right) places” means that they play havoc with the words of God and misinterpret His Book, taking it to mean things that were never meant and attributing to God things that He never said; may God protect us from that.

“[They] have abandoned a good part of the Message that was sent to them” means that they stopped following its teachings because they did not want to follow them. Al-Hasan said: “They did not adhere to their religion or keep their duties towards God, without which no deeds are acceptable to Him; their fitrah (innate nature) was not sound and their deeds were not righteous.” [Tafseer Ibn Katheer]

So it becomes quite clear that the ways in which the Children of Israel tampered with the Torahand Injeel include the following:

Changing Omitting Adding things and attributing to God words that He did not say Misinterpreting the words of God.

When Muhammad (peace and blessings of God be upon him) was sent, the original Torah and Injeel had already been altered and distorted. God revealed the Qur’aan to His Prophet Muhammad (peace and blessings of God be upon him), and guaranteed that He Himself would preserve it, as He says (interpretation of the meaning): “Verily We: it is We Who have sent down the Dhikr (i.e., the Qur’aan) and surely, We will guard it (from corruption).” [al-Hijr 15:9]

This distinguishing feature was not found in any Book before the Qur’aan. From the time of Muhammad (peace and blessings of God be upon him) until the present (more than fourteen hundred years) the Qur’aan has stayed the same, and not a single letter of it has been changed, as ancient manuscripts and the hearts of generation after generation of people who have memorized the entire text and earned the title of “haafiz” bear witness. We ask God to guide us to the true and straight path. And God knows best.