Walking represents living, and usually means living according to the true things taught to us by the Lord -- to "walk in His ways." When the Lord is pictured walking, it means life itself.

12. From these things it can now be established that the Lord dwells with the angels of heaven in what is His own, and thus that the Lord is the All in all things of heaven. The reason for this is that Good from the Lord is the Lord with the angels, for that which is from Him is Himself. Similarly it is plain that it is Good from the Lord which is heaven for the angels, and not anything of their proprium.