Legalism is the belief that you can make yourself more righteous, justified, accepted, loved, etc. before a holy God.
The Law was given to guide the nation of Israel, not as a measure of righteousness. Somewhere along the line, the Law had been perverted as a means to prove righteousness instead of revealing our unrighteousness and need for a Savior.
Jesus shows us through two popular stories how He is more than a prophet. He is a provider, a protector, and God in the flesh. We also see how we are to view our circumstances from God's perspective, not man's.
The last time we looked at Mark, Jesus had just sent out the twelve two-by-two. He commanded them to GO. We then get a break in the story that initially doesn’t make sense. It is the only story in the gospel of Mark that doesn’t directly involve Jesus. The disciples return in v. 30 to give a report to Jesus. So, why this interruption in the story about the disciples training? One reason is to show what you get for faithful service to God. Jesus was calling these men to a mission that will consume their lives. What’s the cost? We see it in these verses.