The secret things belong to the LORD our God, but the things that are revealed belong to us and to our children forever, that we may do all the words of this law (Deuteronomy 29:29)
“The book of Deuteronomy records Moses’ words to the Israelites as they waited on the plains of Moab to enter Canaan. Moses begins by reviewing the events of Israel’s last journey from Mount Sinai to the plains of Moab.”  In the previous Chapters, God set forth commandments for the Israelites with its commensurate promises when obeyed and threats of punishments for disobedience.
In this verse, there are at least three important things to consider. The secret things of God contrasted with the Revealed things of God and the end of God’s revealed will; that is, obedience
The Secret Things.
The Hebrew word translated as secret is hannistārōṯ ; meaning to hide or conceal. This teaches there are some things God has hidden or concealed from humankind. Scripture teaches clearly that God has revealed Himself to humankind in two distinct ways: general revelation and special revelation (Ps. 19:1-3; Rom 1:19-20; Heb. 1:1-2).
However, though God has revealed Himself to humankind and can be known and related with, He has not revealed everything there is to know about himself, his ways and his will to us. There are things that have been held back from us. Some commentators have argued that, Moses, not knowing what lies ahead in their sojourning calls the people to trust in God for that uncertain future:
The reference to “secret things” may suggest that Moses anticipates the uncertain future of the nation, remembering their waywardness and how they turned to the golden calf at Horeb (Ex. 32). In his uncertainty, Moses trusts the hidden future to his trust worthy God. 
Throughout the Bible, we see many instances that speaks of God having a hidden or concealed “things” which humans do not have the capacity to comprehend. One of the first instances we see this is the call of Abraham. The Bible tells us when God called him, he went not knowing where he was going (Heb. 11:8). This indicates Abraham had no road map so to speak, yet he obeyed God. God also provided Abraham with no plan; his ways were kept secret from Abraham. Concerning salvation and the oft debated doctrine of election; Paul argues that God works all things according to His will (Eph. 1:5; 11; Rom 9:11). When speaking to his disciples about the end time or when God will restore the Kingdom to Israel, Jesus spoke of these things in terms of a secret or hidden plan of God (Matt. 24:36; Acts 1:6-7).
Apart from these, there are many other aspects of life God has told us nothing about. For example nobody knows with certainty what will happen the next hour or day or even week. All of these things have been held back from us. Unfortunately, some people have made it their aim to know beyond things God has revealed. This has caused many people unnecessary heartaches for in the long run; they are unable to figure out many of the things they seek out for.
The Revealed Things
As has already been said, there is a contrast between the secret things of God and the things that has been revealed. And that contrast is done with the word “but”: “The secret things belong to the LORD our God, but the things that are revealed belong to us and to our children forever.” (Emphasis mine). This contrast brings us into what can be termed God’s revealed will. Though there are things hidden by God from us, there are those things that have been clearly revealed to us in God’s laws and commandments. In Deuteronomy, Moses continues to pronounce God’s laws and commandments to the people. And it is in these that God has revealed things to the Israelites. In God’s laws, we find what God wants and requires of us. The Christian’s marching order or rule of life is the Bible that tells us how to live for God and please him:
The whole counsel of God, concerning all things necessary for His own glory, man’s salvation, faith and life, is either expressly set down in Scripture, or by good and necessary consequence may be deduced from Scripture. 
One clear example of God’s revealed will in Scripture is found in 1Thessalonian 4:3 “For this is the will of God, your sanctification: that you abstain from sexual immorality.” God’s commandments are not hidden from us because in them we are able to know God and know what pleases Him. God in his laws sets forth promises and threats of punishments when his laws are broken (Deut. 28). Another truth taught about the revealed will of God is its timelessness; the word is relevant for all generations—“the things that are revealed belong to us and to our children forever.” (see vv. 14-15)
There is a purpose for which God reveals His will, that he may be obeyed: “that we may do all the words of this law.” The law of God is not revealed to be only known. It is revealed to be, most importantly, obeyed. What God has revealed is to bring us to the saving knowledge of Christ and of his ways. Scripture is given so we may know, believe and observe what is written. Beyond this, there is no other reason for the word. The word is to be obeyed to keep us from sinning against God. Now to obey is to live in conformity to God’s revealed will (Rom. 12:1-2).
Repeatedly, while giving out the commandments of God, Moses reiterates the importance of obedience to that command: “Therefore keep the words of this covenant and do them, that you may prosper in all that you do” (v.9; cf 18). The prove of our love for God is obedience to his revealed will. Jesus said if we love him, we should keep his commandment, which is his word (1 Jn. 5:3). It is not enough to know God’s will; we must also obey and do it.
We may not know all of God’s ways but He has revealed enough in his word to bring us into a fruitful relationship with Him. Often, we ignore what God has revealed and pursue after things we have no business or right to pursue. This Scripture, Deuteronomy 29:29 therefore teaches us very vital lessons in our walk with God. There are things hidden we cannot know however we try. That should bring us peace. Also, there are things God has made plain and those things must necessarily guide us in our walk with God and in obedience to his word.
1. Paul Barker, “Introduction To Deuteronomy” in The Global ESV Study Bible, (ed. Parker J.I. et al.; Introduction to Deuteronomy, Crossway 2012
2. Strong’s Concordance 5641
3. Study notes on Deuteronomy 29:29, in The Reformation Study Bible ESV (ed. R.C. Sproul et al; Reformation Trust Publishing, 2015) ebook edition.
4 Westminster Confession of faith 1.6