How we should serve God on the Lord's day

Remember that thou keep holy the Sabbath Day
Ex. 20, 8

Man is bound to keep feast days holy. Now a thing is said to be holy in one of two ways, either because the thing is itself unspotted or because it is consecrated to God. We must say something then of the kind of works from which we should abstain on such days and also of the kind with which we should occupy ourselves.

1. Sacrifices. In Sacred Scripture (Nm. 28, 3 it is related how God commanded that every day, in the morning and again in the evening, a lamb should be offered up, but that on the sabbath this offering should be doubled. This teaches us that we too ought on the sabbath to offer a sacrifice, a sacrifice taken from all that I possess.

1. We ought to make an offering of our soul, lamenting our sins and giving thanks for the benefits we have received. Let my prayer, O Lord, be directed as incense in thy sight (Ps. 140, 2). Feast days are instituted to give us spiritual joy, and the means to this is prayer. Whence on such days we should multiply our prayers.
2. We should offer our body. I beseech you therefore brethren, says St. Paul, by the mercy of God, that you offer your bodies a living sacrifice, holy, pleasing unto God (Rm. 12, 1). And we should give praise to God. The psalm says, The sacrifice of praise shall glorify me (Ps. 159, 23). Wherefore on feast days hymns should be numerous.
3. We should offer our goods, and this by giving alms — by giving on feast days a double amount, for these are times of universal rejoicing.

2. Study of the word of God. This indeed was the practice of the Jews, as we read in the Acts of the Apostles (xfii. 27). The voices of the prophets, which are read every sabbath. Christians therefore, whose spiritual state should be more perfect than that of the Jews, ought on such days to meet together for sermons and for the Church's office. And likewise for profitable conversation. Here are two things truly profitable for the soul of the sinner, sure means to his amendment. For the word of God instructs the ignorant and stirs up those that are lukewarm.

3. Direct occupation with the things of God. This do those who are perfect. In the psalms (Ps. 33, 9) we read, Taste and see that the Lord is sweet, and this because He gives rest to the soul. For just as the body worn out with toil craves for rest, so too does the soul. Now the soul's place is God. Be thou unto me a God, a protector and a place of refuge, is written in the Psalms (Ps. 30, 3). And St. Paul, too, says, There remaineth therefore a day of rest for the people of God; for he that is entered into his rest, the same also hath rested from his works, as God aid from his (Hb. 4, 9-10). Again in the book of Wisdom (viii. 16), When I go into my house, that is, my conscience, I shall repose with her, that is, with Wisdom.

But before the soul can attain to this peace, it must already have found peace in three other ways.

It must have peace from the uneasiness of sin.

The heart of the wicked man is like a raging sea, which cannot rest (Is. 57, 20).

It must have peace from the attractions of bodily desires. For the flesh lusteth against the spirit, and the spirit against the flesh (Gl. 5, 17).

It must have peace from the cares of everyday life. Martha, Martha, thou art careful and art troubled about many things (Lc. 10, 41).

But after these are attained the soul shall truly rest in God. If thou call the sabbath delightful . then shalt thou be delighted in the Lord (Is. 1viii. 14). It is for this that the saints have left all things, for this is that treasure which a man having found, hid it, and for joy thereof goeth and selleth all that he hath, and buyeth (Mt. 13, 44). For this is the peace of eternal life and of the joy that shall last for ever, This is my rest for ever and ever: here I dwell, for I have chosen it (Ps. 131, 4).

(In Decalog. 17.)