This rendering of the principle that is given there in I Samuel 16:7 is much more profound because it shows that there is absolutely no possibility - that it is absolutely vain to deceive ourselves - into thinking that we can somehow escape the notice of God. All insincerity, unbelief, and hypocrisy will be detected by Him.
On the more positive side, we are meant to understand that since are hearts are perfectly open before Him, that we should be sincere and make no attempt to deceive others, because that sin is in reality against Him. All sin is against Him because it is His law that is being violated and all of us are His creation. Everything belongs to Him.
Suppose some little girl had a little doll and you destroyed that doll. On one hand the sin is against the little girl because she lost a cherished item, something that was close to her. But even more so, the sin was against the little girl because the doll belonged to her. Though some damage is against the doll, the greater damage, the greater sin is against the one who owned it.
That is the way it is with us and our sins. People get caught in our sins, but the real sin is against God because He owns us, all of us, the whole creation.
Let us add another thought here. Do not lose your place here in Hebrew 4. We are just going to add something to it out of the Psalms. It is another thought that reinforces the thought that is there in Hebrews 4.