And he shall kill the lamb of the trespass offering, and the priest shall take some of the blood of the trespass offering, and put it upon the tip of the right ear of him that is to be cleansed, and upon the thumb of his right hand, and upon the great toe of his right foot:

Wesley's Notes

14:25 The priest shall put the blood - Upon the extremities of the body, to include the whole. And some of the oil was afterwards put in the same places upon the blood. That blood seems to have been a token of forgiveness, the oil of healing: For God first forgiveth our iniquities, and then healeth our diseases. When the leper was anointed, the oil must have blood under it, to signify that all the graces and comforts of the spirit, all his sanctifying influences are owing to the death of Christ. It is by his blood alone that we are sanctified.

Matthew Henry's Concise Commentary

14:10-32 The cleansed leper was to be presented to the Lord, with his offerings. When God has restored us to enjoy public worship again, after sickness, distance, or otherwise, we should testify our thanksgiving by our diligent use of the liberty. And both we and our offerings must be presented before the Lord, by the Priest that made us clean, even our Lord Jesus. Beside the usual rites of the trespass-offering, some of the blood, and some of the oil, was to be put upon him that was to be cleansed. Wherever the blood of Christ is applied for justification, the oil of the Spirit is applied for sanctification; these two cannot be separated. We have here the gracious provision the law made for poor lepers. The poor are as welcome to God's altar as the rich. But though a meaner sacrifice was accepted from the poor, yet the same ceremony was used for the rich; their souls are as precious, and Christ and his gospel are the same to both. Even for the poor one lamb was necessary. No sinner could be saved, had it not been for the Lamb that was slain, and hath redeemed us to God with his blood.

Matthew Henry's Whole Bible Commentary

Verses 21-32

We have here the gracious provision which the law made for the cleansing of poor lepers. If they were not able to bring three lambs, and three tenth-deals of flour, they must bring one lamb, and one tenth-deal of flour, and, instead of the other two lambs, two turtle-doves or two young pigeons, v. 21, 22. Here see, 1. That the poverty of the person concerned would not excuse him if he brought no offering at all. Let none think that because they are poor God requires no service from them, since he has considered them, and demands that which it is in the power of the poorest to give. "My son, give me thy heart, and with that the calves of thy lips shall be accepted instead of the calves of the stall." 2. That God expected from those who were poor only according to their ability; his commandments are not grievous, nor does he make us to serve with an offering. The poor are as welcome to God's altar as the rich; and, if there be first a willing mind and an honest heart, two pigeons, when they are the utmost a man is able to get, are as acceptable to God as two lambs; for he requires according to what a man has and not according to what he has not. But it is observable that though a meaner sacrifice was accepted from the poor, yet the very same ceremony was used for them as was for the rich; for their souls are as precious and Christ and his gospel are the same to both. Let not us therefore have the faith of our Lord Jesus Christ with respect of persons, Jam. 2:1.