The place is holy; God is there. Later it is said that God speaks face to face with Moses (Numbers 12:8). The relationship between God and Moses is confidential, but at the same time Moses has to keep distance; he has to fear the Lord (see Exodus 3:2).
5 Dieu dit: N'approche pas d'ici, ôte tes souliers de tes pieds, car le lieu sur lequel tu te tiens est une terre sainte.