Should I get a contract saying that money was received was a gift and not a loan so it can't be retracted in the future?

I have been wanting to visit a friend of mine for a long time. I was planning on visiting him next summer, but expressed my financial problems and was unsure of whether or not I could save enough money. He generously offered to give me some money because he wants me to visit, and believed that both of us putting some money forward would allow me to visit when I wanted to. I trust him, but I also want to have a backup plan if he decides down the line that the money he wants to give me was a loan. What should I do before taking any money from him that clearly states the money is a gift and not a loan I need to pay back in the future?