Though the Christian Life begins with Sitting, Sitting is always followed by Walking.
When once we have been Well and Truly Seated and have found our Strength in Sitting Down, then we do in fact begin to Walk.
Sitting describes our Position with Christ in the Heavenlies.
Walking is the Practical Outworking of that Heavenly Position here on earth.
As a Heavenly People we are required to Bear the Stamp of that Heavenliness upon us in our earthly conduct.