This is how we know that we know him: if we keep his commandments.

 (iii) In the Old Testament itself, and in the times between the Old and the New Testaments, the last days become associated with the Day of the Lord. No conception is more deeply interwoven into Scripture than this. The Jews had come to believe that all time was divided into two ages. In between this present age, which was wholly evil, and the age to come, which was the golden time of God's supremacy there was the Day of the Lord, the last days, which would be a time of terror, of cosmic dissolution and of judgment, the birthpangs of the new age. 