Mountain-moving is a euphemism for what is humanly impossible but possible for God. Faith is weak (mustard seed), not strong — the emphasis is that you don't earn miracles; God does everything, you just believe.

The teaching is consistent with Mark's broader theme: Jesus heals the paralytic (impossible), heals the blind (only God can), says rich man's salvation is impossible "but with God all things are possible" (Mark 10:25-27). Prayer accesses God's power through faith. Key insight: faith is WEAK, not strong. Jesus says faith the size of a mustard seed moves mountains — because the emphasis is that YOU don't do it, GOD does. This parallels how salvation is by faith (not works). Galatians 3:5: "Does he who provides you with the Spirit and works miracles among you do it by the works of the law or by hearing with faith?" Miracles, like salvation, come by grace through faith — you didn't earn them. Prosperity preachers make faith MASSIVE; Jesus makes it tiny.