I have read these verses many times before, but it's been more illuminating to me now than ever. I've been tutoring a little boy who is in 1st grade, and he wants every tutoring session to be turned into a game. If the session is not fun or exciting, than he shows lack of interest in learning the material. So I had to have a conversation with him that it's practice time not play time. And it's normal that during practice time, he will not always find it exciting, and sometimes he will find the sessions even hard and painful. However, if he endures and studies hard, in the end, it will all be worth it. Thankfully, he understood what I was trying to convey because he has improved a lot since he started tutoring with me and tasted the fruit of his hard work.
Hebrews 12:2-3 state that the reason Jesus was able to endure such excruciating pain and suffering was because of the joy set before him. It's crazy to think Jesus was willing to endure the cross, but for Jesus, it was going to be worth it - to save the lost and be united with His bride for eternity. It's important to note that the reward was what helped Jesus to endure the cross.
Application: Just like this little boy, we all strive for happiness. But more often than not, we find ourselves discontented and disappointed with life and that life is just hard. Life is a battlefield where we need to put on the armor of God due to spiritual warfare and our own sinful flesh. And when I'm discouraged and weary, I just need to remind myself like I reminded the little boy that I'm not in heaven yet (it's not play time haha), but if I endure well, fight the good fight of faith (1 Tim 6:12) and run the race well (1 Corinthians 9:24-27), it will all be worth it when I get to heaven.
Side note: Romans 8:18 is another passage that talks about enduring God ordained trials and how it will all be worth it at the end.