Christ entered into this world for the sake of establishing the Way, the one and only true Gate that leads to God the Father. Those of us who enter through this gate are granted a holy desire to share this gift of communion, because at the core of divine communion is love, characterised by service and total self giving.
When we grow in holiness we grow to be missionaries too. We become a servant of the mission of Christ and also a servant of those around us near and far. When we share the good news of salvation with our brothers and sisters, especially with those who have not known the "only way", we serve them. This service is a fitting response to the great mercy and love of God who saves us and grants us everlasting life.
There is an inseparable link between holiness and mission. Holiness does not exist without mission and mission does not exist without holiness. Only if we are united to Christ as the branches to the vine (John 15:5) can we produce good fruit. Mission is the good fruit we produce when we unite with Jesus the vine. Jesus warns, if the branch separates itself from the vine, it withers and dies.
The effectiveness of mission is determined by holiness. Holiness is the unwavering faith and reliance in the saving power of God. Holiness of a person is in proportion to the grace he has. Venial sin weakens the grace and mortal sin removes grace completely.
The life that God offers us is supernatural. So the means to this end is also supernatural. Sacraments offer us the supernatural grace to grow in holiness. No amount of human effort is sufficient to make ourselves holy or to obtain eternal life. Only the grace of Christ can make us holy and grant us eternal life. Grace is the free merit we receive from redeeming sacrifice of Jesus on the cross. But Christ cannot grant us these things without our cooperation and effort. Our effort is to sincerely and consistently choose to serve Christ and Him alone. Our effort is to constantly fight the battle against the lust of the body, lures of the world and the tricks of the devil.
Our fallen nature draws us towards self seeking choices. We need the grace of God to make the right choices. Our choices must lead us to life. Sin leads us to death. Every time we compromise and give in to sin, thinking God is merciful and will forgive us, we run the risk loosing the grace and becoming more vulnerable to bigger and graver sins. Same happens even when we postpone our return. In order to remain in the state of grace one must humbly admit his frailty, drawing himself immediately to the sacraments, especially reconciliation and the Holy Eucharist, the means of supernatural grace Christ himself has established.
Mission is also letting the Holy Spirit in us to freely move and act according to its will. It is the Holy spirit that convict and turn people to the saving power of Christ.