There are indications that Tehran is worried that Hezbollah may lose this fight. Iran is trying to rush additional rockets to Hezbollah via Syria, even though there is not indication that Hezbollah needs them as yet.
Ever since the fighting began, Iran has been transferring rockets and other ammunition to Hezbollah via Syria. The war materiel moves into Lebanon on trucks from Syria, but much of it is being destroyed by the Israel Defense Forces.
The Iranian resupply effort should not be interpreted as stemming from a serious Hezbollah logistical plight. There are no indications that Hezbollah is running out of rockets, though it may need other equipment. It is possible that the supplies are meant to build up Hezbollah s arsenal in case the war turns into one of attrition.
Iran's embassy in Beirut is coordinating Tehran's involvement in the fighting against Israel. The families of the Iranian advisers have been evacuated, but it is unlikely that Israel will take the extreme step of targeting the Iranian embassy. Iran's Revolutionary Guards also provide constant intelligence and logistical report to Hezbollah's foreign operations unit.
The meaning of Tehran's support is that it is very important to Iran that Hezbollah not be crushed during this confrontation. There are signs suggesting that both Tehran and Damascus are worried that Hezbollah will be worn out by the fighting. Therefore, Iran is pressuring Syria not to acquiesce to diplomatic offers that are meant to pressure or influence Hezbollah and Hamas to hold back on their attacks against Israel.
A couple of things come to mind here; Iran could be worried that the smuggling of weapons to Hezbollah may become significantly more difficult if a true multinational force takes over in Southern Lebanon and is trying to get as much material in before that happens. It's also possible that Iran badly miscalculated Israels response and Hezbollah's value as a strategic threat is in jeopardy unless Iran can prop them up. The fact that Hamas may well be folding is probably not exactly making Tehran at all happy at the moment.
Rushing additional rockets to Lebanon sounds all very well and good, but just how are they doing that? There’s a ton of Coalition forces between them and Syria and plenty of maritime interdiction going on. Are they resupplying by air?
Seems like Tehran is aiming for a Pyrrhic victory. If Hizballah is still able to fire even a single rocket into Israel after IDF operations end, Iran/Syria/Hizballah can claim that they “won,” that they survived the Zionist onslaught, etc.
Nevermind the fact that such a victory will come at the cost of a sizable chunk of Lebanon’s infrastructure and hundreds of civilian lives (the countrymen Hizballah claims to be fighting for). Hizballah, and their Iranian and Syrian backers, will be able to claim victory.
It’s like Gamal Abdel Nasser once said about why he kept invading Israel: “because we can lose 100 times, but they only have to lose once.”
The rockets are likely either brought to Syria from Iran by ship or by air. They try to smuggle them to Hezbollah by truck.