Is it a false teaching?

Is once saved, always saved a true teaching? Can a person lose their salvation? Is continued forgiveness conditional? Is it a good idea not to forgive others after being saved? In other words, can forgiveness be lost by being unmerciful to others, including yourself, (refusing to forgive them, not being merciful)? Some say you can’t lose your forgiveness (salvation is one and done). Hopefully the following verses will shed some light on this topic. This is a KJV Bible study guide. Please read this parable completely, Matthew 18:21-35 (verses 34 and 35 are very important). When I study this it seems very clear to me that one can definitely lose their salvation. [If God can forgive you for the sins you have committed, why can't you do as He does and forgive someone else, including yourself? I believe our attitudes and actions need to mirror God's as close as possible. If not, we may lose our forgiveness. I believe these verses are talking about what we must do after we have been forgiven. The salvation is still there; Jesus didn't make a mistake, the unmerciful servant made a mistake. “Truly” repent and get back on track (Revelation 2:5). When a person chooses not to forgive another, what have they done? They have not done as God tells us to do in Matthew 6:14-15; that is called disobedience. Does God want an unforgiving, disobedient person in His presence? Might be something to research. Food for thought: Some find it hard to forgive themselves. Why? God can and does forgive you. Are your standards higher than His? I don’t think so. Learn what God says and believe Him. If you never study the Bible you will believe what another man tells you; you have just set yourself up to be deceived]. Romans 1:31 Without understanding, covenant breakers, without natural affection, implacable, unmerciful.[Being implacable and unmerciful (not able to be pleased and not willing to forgive) is why we came here to this verse. If a person commits such things, what are they worthy of? Read the next verse, Romans 1:32].What could possibly be one reason for not forgiving others? Matthew 7:3 And why beholdest thou the mote that is in thy brother's eye, but considerest not the beam that is in thine own eye? [Some believe they are better than others maybe, they can't see their own faults. Are they any better than others]? Romans 3:23 For all have sinned, and come short of the glory of God; [Is anyone excluded in this verse? We are all in the same boat]. Jesus' advice to all of us! Matthew 7:5 Thou hypocrite, first cast out the beam out of thine own eye; and then shalt thou see clearly to cast out the mote out of thy brother's eye. [Don't be a hypocrite, (holier than thou sort, pointing out faults in others); clean up your own act first by truly repenting. Then you can truly help others]. Will all professed Christians enter the Kingdom of God? 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. Luke 9:62 And Jesus said unto him, No man, having put his hand to the plough, and looking back, is fit for the kingdom of God."
[The above verse says not all professed Christians will enter heaven; if you turn your back on God, you will not enter the gates of heaven. That is very plain to me. Not a good idea to fall away and look back; go back to sinful ways without repentance. See Ezekiel 33:13 and 18; Hebrews 3:13-14 and 6:4-6 also].Try this website: (I don’t agree with 100% of it but I do agree with most of it).https://www.preparingforeternity.com/oncesave.htmPertinent verses: Matthew 19:25-26.I’m not telling anyone what to believe; I believe everyone needs to study, pray on it and make up their own mind. Let every man be fully persuaded in his own mind. Continue to study the Bible completely as we are commanded to do in the following verse:2 Timothy 2:15 Study to show thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.