Numbers 5-8

The people of God are to be pure (Lev.5v1-4). Though we fail to be perfectly holy, we are pure in the eyes of God because Christ came and lived a life of purity in every respect on our behalf. He was the perfect 'people of God'. The Levites are chosen for a particular service to God - 'I set them apart for myself' (8v17). God also sets the retirement age at 50 - Bonus!