"We know that we have come to know him if we keep his commands. Whoever says, 'I know him,' but does not do what he commands is a liar, and the truth is not in that person." (1 John 2:3-4)
"ginōskō" here, which is about knowing God like you know your best friend, not just having Him as a contact in your phone.
II. The Solution: Put Your Money Where Your Mouth Is (vv 5-6) AKA OBEY
"But if anyone obeys his word, love for God is truly made complete in them. This is how we know we are in him: Whoever claims to live in him must live as Jesus did."