A leash is to lead or restrain. The whole message of the gospel is that God sent Jesus to unleash us from sin.
So, is your faith on a leash or, being a little more blunt, do you have God on a leash? Faith moves us out of the boat—ask Peter. Faith moves mountains. Faith asks us to not walk by sight but to trust in the presence and promises of God. We must unleash our faith from fear, apathy, pride, or any other leashes we are holding that keep us from true freedom and experiencing fullness of God.