The Catechism in Questions & Answers

393. How did their missionary activity proceed?

The Apostles took many troubles, hardships, and sufferings upon themselves in the service of Christ. Apostle Paul describes his experiences in 2 Corinthians 11: 25-28: “Three times I was beaten with rods; once I was stoned; three times I was shipwrecked; a night and a day I have been in the deep; in journeys often, in perils of waters, in perils of robbers, in perils of my own countrymen, in perils of the Gentiles, in perils in the city, in perils in the wilderness, in perils in the sea, in perils among false brethren; in weariness and toil, in sleeplessness often, in hunger and thirst, in fastings often, in cold and nakedness— besides the other things, what comes upon me daily: my deep concern for all the churches.”
Many of the believers fled from Jerusalem on account of the persecutions they suffered there (cf. Acts 8: 1; 11: 19). Even in their new surroundings they acquainted people with the Christian faith and proclaimed the word of the Lord, like Philip, for example, in the capital city of Samaria.

The term ‘mission’ derives from the Latin and means “task” or “mandate”. This term is used in reference to the effort of winning non-Christians over to the Christian faith, the gospel