I will wash my hands in innocence; so I will go about Your altar, O Lord.
Where it belongs in the service
The washing appears as the priest prepares to offer and serve at the altar. In the Offering of the Lamb and again within the Eucharistic order, the priest’s hands are connected with receiving, blessing, touching, and distributing holy things. The visible washing teaches that the priestly service is approached with repentance, humility, and attention.
The action is also a prayer in the body. The priest stands before God on behalf of the people, and his service must be shaped by purity of heart. The water expresses the Church’s desire that the one serving the mysteries should approach with clean hands and a clean heart.
What the gesture teaches
Small actions in the Liturgy often carry theological meaning. This one says that the altar is holy, that service requires preparation, and that the priest approaches the mystery by prayer rather than personal confidence. The faithful see the gesture and learn the same lesson: holy things are received with repentance, sobriety, and reverence.
The washing also connects the service to the wider biblical pattern of approaching God with purity. The altar is holy, the Eucharist is the holy mystery of Christ’s Body and Blood, and the priest’s washed hands become one visible sign that the whole Liturgy is ordered around the holiness of God and the mercy by which His people approach Him.