That is the first question set out in the Westminster Shorter Catechism compiled at the Westminster Assembly of divines (theologians) that met in London in 1644.  It was a catechism, or question and answer manual of instruction, intended for a united Church of all of Great Britain and Ireland, but it ended up becoming the catechism of only the Church of Scotland, and of other Presbyterian denominations.  But it is a good catechism nonetheless, and it is a good opening question.

In this week's Sunday sermon, the Rev Robert West continues with his exposition of Hebrews chapter 2 with verse 10, and explains that the atoning work of Christ upon the cross brings glory, not shame, to God; that this sacrifice for sin brings many, but not all, to eternal redemption; and that in achieving so costly and so precious a result the eternal Son of God, become man, became perfected in His office as mediator, and saviour, by the things which He suffered.  
His sufferings were redemptive in intent and outcome.  We can add nothing to it for it is Christ that has achieved eternal redemption for His people - those who truly believe in Him.