Albert Barnes on 1 John 2:28

And now, little children. 1Jn 2:1. Abide in him; that, when he shall appear. In the end of the world, to receive his people to himself. Jn 14:2,3. We may have confidence. Greek, boldness--παρρησιαν. This word is commonly used to denote openness, plainness, or boldness in speaking, Mk 8:32, Jn 7:4,13,26, Acts 2:29, 4:13,29, 2Cor 3:12, 7:4. Here it means the kind of boldness, or calm assurance, which arises from evidence of piety, and of preparation for heaven. It means that they would not be overwhelmed and confounded at the coming of the Saviour, by its being then found that all their hopes were fallacious.

And not be ashamed before him at his coming. By having all our hopes taken away; by being held up to the universe as guilty and condemned. We feel ashamed when our hopes are disappointed; when it is shown that we have a character different from what we professed to have; when our pretensions to goodness are stripped off, and the heart is made bare. Many will thus be ashamed in the last day, (Mt 7:21-23;) but it is one of the promises made to those who truly believe on the Saviour, that they shall never be ashamed or confounded. 1Pet 2:6, Comp. Isa 45:17, Rom 5:5, 1Pet 4:16, Mk 8:38.