This study is based upon the New City Catechism.
“Every one of you shall revere his mother and his father, and you shall keep my Sabbaths: I am the Lord your God.” (Leviticus 19:3)
God called Israel to holiness in Leviticus 19:1-2 on the basis of His own holiness, and the first instruction He gave Moses was the fourth and fifth commandments (v.3). God linked these two commandments into one admonition, making plain that active obedience looks first and foremost like Sabbath keeping and honoring one’s parents. God considered these two commands together; we should do the same.
The first three and final five commandments of the Decalogue (Exodus 20:1-17) are negative commands – they teach what not to do. To break a negative command would be a sin of commission: committing an act forbidden by God. Only commands four and five are positive. These positive commands teach what should be done. To break a positive command would be a sin of omission: omitting something God explicitly said needed to be done.
By the above metrics, 80% of keeping God’s law has to do with staying away from certain things and 20% with doing other things. Keeping the Ten Commandments is mostly about not acting – not doing certain things which God considers wicked. Holiness to God is like a mountain; God wants us to stay on the top. There are many ways to fall off the mountain, but there is only one way to remain: stay put. In our fallen world, there are many more wicked and perverse things than there are righteous things. Living a holy life before God is not complicated. What’s complicated is saying no to the dozens and dozens of evils that we are presented with daily. This is why Jesus calls salvation the straight and narrow path (Matthew 7:13-14).
First, notice the difference in subject. The fourth commandment concerns God; the fifth commandment concerns man. The fourth commandment reflects back upon the first three, which concern our relation to God; the fifth commandment anticipates the last five, which concern our relation to other people. Further, the fourth commandment is cyclical (i.e. can only be obeyed once per week); the fifth commandment is continual (i.e. can be obeyed all the time).
Second, notice the difference in basis. The fourth commandment is given on grounds of creation. God created the universe in six days, and on the seventh day He rested. Our weeks should reflect the very first week, when God created all things (Exodus 20:9; cf. Genesis 1). Motivation for keeping the fourth commandment is found in God’s creational blessing of the seventh day (Exodus 20:11). The fifth commandment is given on grounds of blessing. Honoring one’s father and mother will lead to long days in the land that God promised Israel (v.12). This longevity is not referring to individual lifespan, but to generational continuance in the Promised Land. God is saying that if Israel honors their parents, then they will not grow bitter and unrepentant towards God. Motivation for keeping the fifth commandment is found in God’s redemptive blessing of parenthood.
Third, notice the difference in New Covenant administration. The fourth commandment calls for honoring the Sabbath, but when Christ rose from the dead He created a new Sabbath. In the Old Covenant, the fourth commandment called for resting on the seventh day of the week, because that’s when God rested from creation. In the New Covenant, the fourth commandment calls for resting on the first (or eighth) day of the week, because that’s when Christ announced our rest in His salvific work. With the change in day there has also come a change in focus. The focus is now redemptive, not creational, which means the works from which we rest are not creational works, but redemptive works (Hebrews 4:9-10). For the Christian church, the fourth commandment calls us to rest in the finished work of Christ on the cross. We publicly demonstrate that rest by spending the Christian Sabbath (Sunday) worshiping God.
The fifth commandment calls for honoring one’s parents, a command applicable in the New Covenant. Even the promise attached to the fifth commandment (Exodus 20:12) remains potent. Paul applied the fifth commandment to New Covenant children in Ephesians 6. “Children, obey your parents in the Lord, for this is right. ‘Honor your father and mother’ (this is the first commandment with a promise)” (vv.1-2). The blessing of the fifth commandment (that those who honor their parents will have God’s saving grace in their future generations) is a promise for New Covenant believers. The only difference is that our Promised Land is not Canaan, it is the New Heavens and New Earth.
Question: What does God require in the fourth and fifth commandments?
Answer: Fourth, that on the Sabbath day we spend time in worship of God. Fifth, that we love and honor our father and our mother.
 Note: I consider the argument, “Because the fourth commandment is not repeated in the New Testament, it therefore is not applicable,” to be invalid.