But sacrifice is here presented in a different aspect from elsewhere in the law. In this ceremonial the central thought is not consecration through sacrifice, as in the burnt-offering; nor expiation of guilt through sacrifice, as in the sin-offering; nor yet satisfaction for trespass committed, as in the guilt-offering. It is sacrifice as procuring for the man for whom it is offered purity and life, which is the main thought. But, according to vv. 52, 53, the atonement is made with both the dead and the living bird. The special thought which is emphasised by the use of the latter, seems to be merely the full completeness of the work of cleansing which has been accomplished through the death of the other bird. For the living bird was represented as ideally identified with the bird which was slain, by being dipped in its blood; and in that it was now loosed from its captivity, this was in token of the fact that the bird, having now given its life to impart cleansing and life to the leper, has fully accomplished that end. Obviously, this explanation is one that will apply no less readily to the cleansing of the leprous house than of the leprous person. For the leprosy in the house signifies the working of corruption and of decay and death in the wall of the house, in a way adapted to its nature, as really as in the case of the person; and the ceremonial with the birds and other material prescribed means the same with it as with the other,--namely, the removal of the principle of corruption and disease, and impartation of purity and wholesomeness. In both cases the sevenfold sprinkling, as in analogous cases elsewhere in the law, signified the completeness of the cleansing, to which nothing was lacking, and also certified to the leper that by this impartation of new life, and by his cleansing, he was again brought into covenant relations with Jehovah. With these ceremonies, the leper's cleansing was now in so far effected that he could enter the camp; only he must first cleanse himself and his clothes with water and shave his hair,--ceremonies which, in their primary meaning, are most naturally explained by the importance of an actual physical cleansing in such a case. Every possible precaution must be taken that by no chance he bring the contagion of his late disease into the camp. Of what special importance in this connection, besides the washing, is the shaving of the hair, will be apparent to all who know how peculiarly retentive is the hair of odours and infections of every kind.