If you read from Matthew 7:13-27 in context at the link below, this is about a warning from Jesus about false prophets coming in leading many professing saved believers astray. https://www.biblegateway.com/passage/?search=Matthew+7:13-27&version=KJV But we shall zero in with this; Matthew 7:21 Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. 22 Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? 23 And then will I profess unto them, I never knew you: depart from me, ye that work iniquity. KJV Now why would Jesus profess to never knowing them in regards to false prophets coming in leading them astray? The key is in verse 23 of the underlined portion of that verse. Titus 1:16 They profess that they know God; but in works they deny him, being abominable, and disobedient, and unto every good work reprobate. KJB The underlined portion of Titus 1:16 is also a clue. Works that deny Him. How is that important? 2 Timothy 2:11 It is a faithful saying: For if we be dead with him, we shall also live with him: 12 If we suffer, we shall also reign with him: if we deny him, he also will deny us: 13 If we believe not, yet he abideth faithful: he cannot deny himself. So any works that deny Him is a professing believer denying Him, and thus He will deny them. This is why Jesus said "I never knew you" to those professing believer because they were workers of iniquity in Matthew 7:23 But do take note of 2 Timothy 2:13 above because even if a saved believer stopped believing in Him, He still abides in those former believers and thus even believers that went astray because He will lose nothing of all the Father has given Him. John 6:39 And this is the Father's will which hath sent me, that of all which he hath given me I should lose nothing, but should raise it up again at the last day. 2 Timothy 2:18 Who concerning the truth have erred, saying that the resurrection is past already; and overthrow the faith of some. 19 Nevertheless the foundation of God standeth sure, having this seal, The Lord knoweth them that are his. And, let every one that nameth the name of Christ depart from iniquity. 20 But in a great house there are not only vessels of gold and of silver, but also of wood and of earth; and some to honour, and some to dishonour. 21 If a man therefore purge himself from these, he shall be a vessel unto honour, sanctified, and meet for the master's use, and prepared unto every good work. What makes a vessel unto dishonor? Iniquity. What makes a vessel of dishonor to become a vessel unto honor? When he departs from iniquity with His help. 2 Timothy 2:21 above. Both of those vessels are still in His House; 2 Timothy 2:20 above So Jesus saying "I never knew you" is because of the iniquity that is denying Him. He still abides in the believer, but the believer is a reprobate, as in, disqualified from attending the Marriage Supper held in His honor. That means the believers will be left behind to be received later on after the great tribulation as a vessel unto dishonor in His House. Luke 13:24-30 at the link below is another version of Matthew 7:13-27, but referring to the sitting down with the O.T saints, of which I receive it to be the Marriage Supper event at the pre tribulational rapture event. https://www.biblegateway.com/passage/?search=Luke+13:24-30&version=KJV There is more than a loss of the rewards of crowns for being in iniquity. A believer can become a castaway. 1 Corinthians 9:24 Know ye not that they which run in a race run all, but one receiveth the prize? So run, that ye may obtain. 25 And every man that striveth for the mastery is temperate in all things. Now they do it to obtain a corruptible crown; but we an incorruptible. 26 I therefore so run, not as uncertainly; so fight I, not as one that beateth the air: 27 But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway.