Always be prepared to give an answer to everyone
who asks you to give the reason for the hope that you have.
(1 Peter 3:15 NIV)
If you know any non-believers, you may at some time be asked to explain and defend your faith. As Peter wrote (see above), we must be ready to respond in those circumstances. You don't need to have a PhD in theology, philosophy, and history; instead just explain what Jesus has done for you.
Nevertheless, it doesn't hurt to know have answers, and more importantly know where to refer people, when they have hard questions about the reality of the Christian faith.
In a nutshell, here's the case for Jesus being God:
- God really exists.
- Jesus really existed.
- He claimed to be divine.
- He predicted his death and resurrection, then did it.
- His resurrection proves point # 3.
Do we have hard evidence for these statements? Rather than reiterate them here, let me direct you to some resources that will provide the answers.
- The Case for Christ / Cold Case Christianity - These 2 book were written by trained investigators (one was a journalist and the other was a police officer who worked on murder cold cases). Each has a similar story; they were avowed atheists whose wives became Christians. They decided to use their skills to learn more (and in one case, disprove) the Christian faith. But when they investigated, they became convinced that Jesus was God, and they became Christians. Each provides an excellent overview of the evidence for Jesus's divinity.
- Cross Examined - This is the YouTube channel run by Frank Turek, author of I Don't Have Enough Faith to Be an Atheist. I haven't read the book so I cannot comment on it, but the YouTube channel has dozens of excellent videos about the faith. Turek tackles the various objections and questions about the reality of God and Jesus. Most videos are short (under 10 minutes) so are not too taxing.
This just skims the surface, but is a good start if you are truly interested in learning more about the evidence behind the Christian faith. Alas, as Turek frequently mentions, many people don't really want to know the truth about Jesus - they are on a happiness quest rather than a truth quest, and Christianity prevents them from what they want to do. I pray that you are on a truth quest, and find these resources helpful.