The holiness of the temple area would be protected in two ways. First, sinners were kept out of the sacred space. Second, the sacrificial system dealt with sin and impurity.
This focus on holiness is clear from the detailed description of the altar in the inner court. The altar stood at the center of the entire temple complex. Its central place shows how important it was.
The altar shown to Ezekiel was much larger than the altar in front of the tabernacle. It was almost three times as long and wide (see Exodus 27:1–8).