To have a happy life, it is essential to be at rest. In explaining the way to find this rest, our Lord says: "Come to Me - Take My yoke upon you and learn from Me - and you will find rest for your souls. For My yoke is easy and My burden is light" (Matt. 11:28-30).
The One who asks us to take His yoke upon us, gave us an example when He submitted to His Father's will saying, "Behold, I have come to do Your will, O God" (Heb. 10:9). To find rest we too must surrender our wills to God's. That's what it means to "take My yoke upon you." Have you ever seen a yoke of oxen? When they are yoked up, they submit their will to the master.
Sin is the cause of all unhappiness in God's universe, and the root of all sin is self-will, or substituting our will for God's. Not only does this bring us into conflict with our Creator, but it also creates a conflict within us.
A child of God receives a new, divine nature when he is born again. This divine nature loves God and hates sin. The Christian also has the Spirit of God dwelling within him. For these reasons, inner conflict arises when a child of God yields to self-will and sin.
When we make something, we have the right to govern its use. Likewise, God has a right to say what we should do, because He has created us. When we buy something, it belongs to us. God has purchased us with the blood of His Son: "You are not your own - you were bought at a price; therefore glorify God in your body and in your spirit, which are God's" (1 Cor. 6:19-20). When a child is born, he is expected to obey his parents. When a person is born again, God expects obedience from him (John 3:3; 1 John 5:18; 1 Pet. 2:1-2).
We cannot disregard God's threefold claim over us — as His creation, His possession and His children — and expect inner peace. We must recognize God's rights. Therefore, if we exert our self-will in rebellion against God's will, inner conflict results.