Is what was attributed to Sheikh Ibn 'Uthaymeen—may Allah have mercy on him—true: that "it is from the Sunnah, if a person sees something that pleases him in this world, to say: 'Labbayk, indeed the true life is the life of the Hereafter'"?

It has been reported from the Prophet, peace and blessings be upon him, that he would remember Allah by saying, "Indeed, the true life is the life of the Hereafter," or "Indeed, the true good is the good of the Hereafter," upon seeing something admirable from this world or facing hardship. Scholars have adopted these hadiths and reports, making it commendable for a person, upon seeing something they admire, to say, "O Allah, indeed the true life is the life of the Hereafter," to remind themselves that the Hereafter is the real life. The Prophet, peace and blessings be upon him, used to say it in times of both hardship and ease.