That you can speak this untruth so casually is discomforting. You appear to believe the lies that are being spouted by someone who is attempting to defame Jacob Blake, without ever having evaluated the original video. If you had seen the video, you never would have made the claim that "he came at the cops with a knife." Who was this person that lied to you in this way? It would be useful to name and shame this individual or group.
Please watch the video, reassess your claim, and cast your doubts upon these people who told you this untruthful story.