We cannot start a service or initiate a work simply because we like it or are enthusiastic. To do so would be to serve God with strange fire, because the service would be of man, not of God. Strange fire is unacceptable to God. It is not what He wants.
The service that God desires is carried out through the fire on the altar of burnt offering. The altar of burnt offering has already been set up, and fire has also descended upon it. The altar of burnt offering is the cross of the Lord Jesus, and the fire is the Spirit [Galatians 2:20; Acts 2:3]. The Spirit has descended and is burning through the cross as the altar of burnt offering. Any person who is willing to touch the cross, that is, to receive the cross by applying the death of Christ, will be gained by God. Then the fire on the altar of burnt offering, that is, the Spirit, will burn in him until it produces a service. All genuine service comes out of such a burning. (The Service for Building Up the House God, ch. 2, by Witness Lee)