It is fairly normal to question our relationship with God. Just think of Thomas. Jesus loved him and chose him as one of the twelve. Jesus knew he would doubt him. Jesus knows we will as well.
John also had his times as well. John also knew it was not only “do I know God”, but do I know Him in the right way? That is the real question. How can I be sure I know God in the right way?
John simplifies it for us. If you want to be sure you know God in the right way, keep his commandments. King Jesus, the anointed Messiah, requires that we obey God. Following Jesus is all about obedience.
John also knows the commandments are about love. Love God. Love everyone else you know or come in contact with. The focus on love makes sure you have the right relationships. It is that simple.
“Here’s how we can be sure that we know God in the right way: Keep his commandments.” ~~Apostle John (1 John 2:2 The Message)