But Noah still needed his ark.

Doug Wilson, on the Westminister Confession's statement that our interest (i.e. stake) in Christ, along with the benefits thereby implied, is confirmed in the sacraments:

Some might say that if you have the faith, then that is sufficient–you can go off by yourself, you and your faith, and do all your confirming of interest away from God's people. The bread and wine are entirely optional if faith is sufficient, right? But if God said to meet Him here in the bread and wine, how is it faith to try to meet Him somewhere else? Detaching faith from the instruments God has appointed is neither right nor safe.

Of course we know from Scripture that evangelical faith is the catalyst. When Namaan was told to wash in the Jordan, it would not have been appropriate for him to conclude that another river, or no river at all, would do just as well–even if he recognized that the Jordan was nothing in itself. In the same way, we insist on the potency of faith alone, which means that the faith must do something other than what unbelief would do.

Come, the bread and wine are here. Confirm your interest in Christ by partaking now, together with your brothers and sisters.

Yes, the efficacy of the ritual is wholly tied to the presence and application of faith. Without faith, the ritual becomes something else entirely different than the covenant confirming, spiritually edifying interaction that the Believer experiences. Even still, that is not to say that the ritual should be done away with or its importance lessened. Remember, Moses was saved by faith, AND by an ark.

Read the rest of Wilson's piece here.