He also repeatedly said he was ready to die for Lebanon - his father, former Prime Minister Rafik Hariri, was killed by a vehicle bomb in Beirut in 2005 - but added that he didn't want his children to go through that kind of ordeal.
The race turned into a political rally, with numerous runners calling for the return of Hariri, who has not publicly spoken since unexpectedly announcing his resignation.
Meanwhile, in a statement released by Aoun's office on Saturday, the Lebanese president expressed concern over Hariri's situation and said the premier was living in a "dubious" situation in Saudi Arabia.
"I have resigned. I am going to Lebanon very soon and I will resign in the constitutional manner", he said in the TV interview. Aoun refused to accept Hariri's resignation unless he tendered it in person in Lebanon.
Lebanon President Michel Aoun said before the interview that the "mysterious circumstances for Hariri's stay in the Saudi capital of Riaydh makes all his positions questionable and in doubt and not of his own volition".
"I am free", Hariri told the interviewer, apparently seeking to show he was not being detained by the Saudis.
Hariri announced his resignation on November 4, citing several reasons, including the security situation in Lebanon, for his sudden decision.
The kingdom has been demanding that Hezbollah play no role in future government, accusing the group of supporting anti-Saudi Yemen rebels known as Houthis.
"Whatever he chooses, we are with him".
He added that a marathon planned in Beirut on Sunday in which tens of thousands are expected to participate should be "a national sports demonstration for solidarity with Prime Minister Hariri and his return to his country". Hariri's family lives in Riyadh.
The announcement comes after Yemeni transport minister Murad Al Halimi said on Friday that airports in the government-held cities of Aden and Seiyun, in Hadramawt province, would be reopening.
Hariri said he "can't be the only one making concessions while the others do whatever they want".
"I am freely in the Kingdom, and if I want to travel tomorrow, I will travel".
Saudi Arabia and the United States have accused Iran of supplying the ballistic missile used in that attack, saying the missiles bore "Iranian markings".