Ukraine tried to purchase Iron Dome rocket defense systems from Israel in 2019 and Israel refused. Israel would not sell weapons to Ukraine before the Russian 2022 invasion because of Russian cooperation in Syria where Israel regularly attacks Iranian forces trying to get close enough to the Israeli border to launch attacks. Israel carries out these air strikes without interference from Russian air defense systems or jet fighters in Syria to support the Assad government against rebels, including a large number of ISIL (Islamic State in Iraq and the Levant) Islamic terrorists.
Israel would not sell any weapons to Ukraine. You won’t see Russian troops using any Israeli weapons either and that is part of the price Israel has to pay to keep its population safe from Iranian attacks and decades of pledges to destroy Israel completely. Iran will use nuclear weapons for this, once it completes development of a workable nuke that is rugged enough to work in a ballistic missile warhead. Israel did send a field hospital to Ukraine and other non-lethal assistance without visibly angering Russia.
Israel has already carried out several major attacks on the Iranian nuclear weapons program. Some were in cooperation with the United States but the most recent ones were done with the help of Iranians who also oppose the nuclear weapons and the current Iranian religious dictatorship. Israel makes it clear it will launch a major air and missile strike against the Iranian nuclear program if Iran gets close to creating a working nuclear weapon. Israel’s new allies among the Arab Persian Gulf oil states will cooperate with such an attack, as they are already being hit by Iranian missiles, cruise missiles and guided rockets.
Israel has had locally developed nuclear weapons since 1970 and used these weapons as the ultimate deterrent to any serious effort to destroy Israel. Israel can deliver their nukes several ways. This first method was aircraft delivered gravity bombs and later via air-to ground missiles. Then came ballistic missiles plus cruise missiles that can be launched via torpedo tubes from a submerged Israeli sub. Israel never acknowledged it has nukes and continues to maintain them and several delivery systems. This has deterred everyone except Iran, which since the 1980s has been ruled by a religious dictatorship that was obsessed with destroying Israel.
Israel has always had good relations with Russia, which was one of the first nations to recognize the new state of Israel in 1948. This played a role in Russian Jews being allowed to migrate to Israel starting in the 1970s. Currently about 15 percent of the Israeli population are either those who migrated from Russia or their descendants. Many of these Russian Jews came from Ukraine, where the current leader is a Jew elected president in 2019 because he backed more economic and security connections with NATO and the West. Despite that Russia worked hard to maintain its good relations with Israel and in 2016 Russian leader Vladimir Putin described Russia and Israel as “unconditional allies”. Thousands of Russian Israelis have demonstrated in support of Ukraine after the recent invasion. The Israeli government refused to openly criticize the Russian invasion of Ukraine but is trying to use its good relationship with Russia to help negotiate an end to the fighting and the war. Israel has reacted to earlier Russian attacks on Ukraine. After the 2014 attacks on Crimea and eastern Ukraine, Israel halted cooperation with Russian efforts to develop modern UAVs. Because of its even closer relationship with the United States, Israel has never provided Russia with lethal weapons or weapons technology. At the same time Israel has sold over a billion dollars’ worth of weapons to Moslem majority Azerbaijan, another former part of the Soviet Union that borders Iran and Russian backed Armenia. In late 2020 there was a brief war between Azerbaijan and Armenia that the Azeris won, in part because of the Israeli weapons. Selling weapons to Ukraine was another matter and Russia apparently told Israel that such sales could reduce Russian cooperation in Syria against Iran. Most Israelis support Ukraine, but the Iranian threat is very real and next door, so Israeli politicians cannot ignore it unless they want to lose their next election. Russia has already suffered major economic losses from the additional economic sanctions imposed after the February 2022 invasion and may end up a much-reduced military power. This could include the withdrawal of their forces in Syria. Even with that, Russia remains a major nuclear power with a large enough arsenal to trigger the nuclear apocalypse that became a reality in the 1960s and has kept the peace between the nuclear powers ever since. Vladimir Putin openly threatens to use nukes to keep NATO nations from supporting Ukraine militarily. NATO is sending in lots of weapons anyway, but not NATO forces. Israel senses a real need to stay off the Russian nuclear targets list.