Hajj is the 'individualised Wish of God' blessed to every soul independently, which it shall live out in this world to the fullest satisfaction of Allah; And 'Unra' is his 'Efforts' towards gaining it through patience, endurance, steadfastness while seeking to strenghen his belief and faith in Him.
2:196
Begin your Hajj and Umra in the Way of Allah; and if you are blocked then preserve in righteousness and persevere; and until you reach your goal, never slacken in the determination; however if any of you due to weakness slackens then his due compensation is: fasting, or to spend for the needy, or to sacrifice from his valuables; and when peace comesforth unto him, let him fulfil to a great extent possible his obligation from Umra to Hajj by giving his valuables; and if this is not possible let him complete ten days’ fasting- three, during the Hajj journey and seven when he is contented; and this is for those whose heart is not upon the sacredness and so fear Allah; and know that Allah is severe in punishing.