On All Saints Day the Church celebrates all the saints: canonized or beatified, and the multitude of those who are in heaven enjoying the beatific vision that are only known to God. 

We all have this "universal call to holiness." What must we to do in order to join the company of the saints in heaven?

The followers of Christ are called by God, not because of their works, but according to His own purpose and grace. They are justified in the Lord Jesus, because in the baptism of faith they truly become (children) of God and sharers in the divine nature. In this way they are really made holy. Then too, by God’s gift, they must hold on to and complete in their lives this holiness they have received. They are warned by the Apostle to live “as becomes saints”,(Eph. 5, 3.) and to put on “as God’s chosen ones, holy and beloved a heart of mercy, kindness, humility, meekness, patience”,(Col . 3, 12.) and to possess the fruit of the Spirit in holiness.(Cf. Gal. 5, 22; Rom. 6, 22.) Since truly we all offend in many things (Cf. Jas. 3, 2.) we all need God’s mercies continually and we all must daily pray: “Forgive us our debts”(Mt. 6, 12.)(Cfr. S. Augustinus Retract. II, 18: PL 32, 637 s. Pius XII Litt. Encycl. Mystici Corporis, 29 iun. 1943: AAS 35 (1943) p. 225.)  - Lumen Gentium 40