"There is nothing hidden that will not be disclosed and nothing concealed that will not be known or brought into the open." Luke 8.17
When I sin I'm conscious that God knows everything I do, so as soon as I am stirred by the Holy Spirit I confess that sin quickly and God forgives me right away.
Acts of service done unto God in secret are not hidden from Him. Even if they are hidden from others God sees and rewards. For instance praying for others, and a host of kind, selfless acts. Those people will be rewarded by God and honoured by Him.
The acts of the wicked are not hidden from God. Though they try to fool others into believing they are right and the righteous are wrong, it is they who will be exposed by God. They can fool some of the people some of the time, but not all the people all the time. They can never fool God who sees all they do clearly. About them God says "It is mine to avenge; I will repay. In due time their foot will slip." Deuteronomy 32.35.