Psalm 119:160 (NKJV)
When someone is called into court to be a witness in a legal case their testimony will begin with them being asked a question, "Do you swear to tell the truth, the whole truth, and nothing but the truth?" and the witness presumably will answer yes. The witness is then asked to tell what they know about the case before the court. The witness is not supposed to give opinions, tell what they heard someone else say, or make a guess about something. The witness is supposed to tell the truth, the whole truth, and nothing but the truth about the questions they are asked.
Psalm 119 is the longest chapter in the Bible and it is all about God's Word. 2 Timothy 2:15 tells us that we need to rightly divide the Word of truth and Ephesians 1:13 says that the Gospel is the Word of truth. God's Word is the truth and it endures forever. What we say is extremely important so when we talk about ourselves, our families, the situations we deal with in life, the challenges we face, our future, and anything else, we need to tell the truth, the whole truth, and nothing but the truth about all of these things, we need to say what the Bible says.
Christians are new creations and the righteousness of God in Christ (2 Corinthians 5:17, 21), able to do all things through Christ (Philippians 4:13), the Lord is the strength of our life (Psalm 27:1), and God will supply all of our needs (Philippians 4:19). We may read about this and it does not seem possible or we somehow feel unworthy of such a thing. But no matter what others have said, what has happened in the past, what things look or feel like it is still true and we have to be sure we tell the truth, the whole truth, and nothing but the truth; we must say what the Bible says. That is how we live a victorious Christian life.