How do we know that faith like a mustard seed is enough?

In Matthew 17:20, Jesus teaches that faith as small as a mustard seed can move mountains, emphasizing that the efficacy of faith is not in its size but in its object, which is Christ. Even the smallest faith can achieve great things because it relies wholly on the power of Christ. This assures believers that they need not possess extraordinary faith; instead, they can trust in the sufficiency of Christ's redemptive work, demonstrating that salvation is secured regardless of the perceived strength of one's faith.