The Greek eklampō means to shine forth brilliantly — to blaze out with radiant light. It appears only once in the New Testament: Matthew 13:43, the conclusion of the Parable of the Weeds — 'Then the righteous will shine like the sun (eklampō) in the kingdom of their Father.' The prefix ek intensifies the shining — a blazing forth from within, as the sun's full radiance.
Matthew 13:43's promise of eklampō is the eschatological destiny of every believer: to shine like the sun in the Father's kingdom. This echoes Daniel 12:3 — 'Those who are wise will shine like the brightness of the heavens, and those who lead many to righteousness, like the stars for ever and ever.' The present hiddenness of the kingdom (mustard seed, leaven) gives way at the harvest to revealed glory. Every believer who now seems insignificant will eklampō in the fullness of Christ's transforming work.