William Burkitt on 1 John 2:28

Still our apostle reinforces his foregoing exhortaion to abide fixedly in Christ; that is, in the doctrine of Christ, in true Christianity; and now, little children, abide in him: And the argument which he makes use of is very forcible and cogent, namely, That when Christ shall appear, we may have confidence,and not be ashamed before him at his coming.

Here note, 1. Something supposed, namely, the coming and appearance of Christ; he shall appear.

2. Something implied, namely, our appearance before Christ in the day of his appearance.

3. Something expressed, namely, the confident appearing before Christ, of all those who abide in him; That we may have confidence, and not be ashamed before him at his coming.

Whence learn, That the persevering Christian shall have confidence before Christ at his coming; shall lift up his head without shame or blushing, from the testimony which conscience bears of his sincerity, and from the interest he has in the Judge; But, on the other hand, they that do not persevere and abide in Christ shall be ashamed before him at his coming; ashamed of their gross hypocrisy, of their vile unfaithfulness, of their manifest folly.