Psalm 119:45 and 47 are delightful lines: “I will walk about at ease” and “I will delight in Your commandments.” That first line is evocative.
The notion is to walk in expansiveness, with room to spare, in freedom. The idea is “relief” (4:1), roominess for the feet as one walks (18:36), freedom from anguish (25:17), opening one’s mouth so God can fill it (81:10), the vastness of the sea (104:25), and the boundlessness of God’s commands (119:96).

The commands, acc to the psalmist, liberate because one hears God, walks with God, and learns of God how to walk in this life. The commands are “roomy” because they provide guidance and sure-footedness to the traveller. They are expansive because they give the observant the sense of confidence, of knowing where they are, as they wander through this life with God.
It is delightful, the psalmist to be at ease with God in this world. It is Torah joy.