These things I have spoken unto you, that in me ye might have peace. In the world ye shall have tribulation: but be of good cheer; I have overcome the world. – John 16:33

The Believer is in two places, and he lives two lives. In the text there are two places spoken of— “in Me” and “in the world.” The saint’s noblest life is “hid with Christ in God.” This is his new life, his spiritual life, his incorruptible life, his everlasting life. Rejoice, Beloved, if you are in Christ, and enjoy the privilege which belongs to that condition— “that in Me you might have peace.” Do not be satisfied without it! It is your right through your relationship to the Prince of Peace. Because you are in Christ, your life is always safe and should be always restful. Your greatest interests are all secure, for they are guaranteed by the Covenant of which Jesus is the Surety. Your treasure, your eternal portion, is laid up with Him in Heaven where neither rust nor robber can enter. Therefore, be of good cheer! Be restful and happy, for you are in Christ and He has said, “These things have I spoken unto you, that in Me you might have peace.”

You are sorrowfully conscience that you also live another life, for you dwell in the midst of evil men, or, as the text puts it, you are “in the world.” I need not enlarge upon that fact, for probably, dear friend, every time you go out to business or to daily labor, you find by the ungodly speeches of graceless men, that you are in the world which lies in the Wicked One. Even while you dwell in the sweet seclusion of domestic life, though your family has been graciously visited, and your dear ones are all Believers, yet even there matters occur which make you feel that you are “in the world—a world of sin and sorrow. You are not yet in Heaven—do not dream that you are. It would be a pity for a sailor to expect the sea to be as stable as the land, for the sea will be the sea to the end and the world will be the world to you as long you are in it. The Savior warns His people, “In the world you shall have tribulation.” …Now, because of this tribulation and the sorrow, which is likely to come of it, our Savior gives us the words of good cheer to which our attention is directed in the text. ~ C.H. Spurgeon

https://www.blueletterbible.org/comm/spurgeon_charles/sermons/3285.cfm