There is a wrong kind of confidence as well as a right one. For example we have the statement in Scripture that “the foolish is overbearing and confident” (Proverbs 14:16). Although not specifically stated the passage suggests that the confidence is really self-confidence. Self confidence is wrong: “He that confideth in his own heart is a fool” (Proverbs 28:26). Then we are warned against putting our confidence in unreliable persons or things. Thus we have it said of one that his “confidence shall be cut off, and his reliance is a spiders web” (Job 8:14). A concordance shows many passages giving such warnings. For examples we have: “Put not confidence in nobles, in a son of man, in whom there is no salvation.” (Psalm 146:3) and again: “Woe to them that go down to Egypt for help, and depend on horses, and confide in chariots because [they are] many, and in horsemen because they are very strong.” (Isaiah 31:1). See also Jeremiah 46:25. We have the consequence of putting our confidence in such in Isaiah 20:5 “And they shall be terrified and ashamed of Ethiopia their confidence, and of Egypt their boast.”Again we have “Cursed is the man that confideth in man, and maketh flesh his arm, and whose heart departeth from Jehovah” (Jeremiah17:5).
We may say that we are well aware that we should trust in God and not ourselves or other people and things, but do we not often trust in our insurances, our friends and maybe the police rather than God? Certainly we should not tempt God by taking silly risks such as Satan suggested to Christ (Matthew 4:5-7). But firstly our trust should be in God and any help we get from elsewhere should be subsidiary and we should accept it only as something that God has provided for our safety and benefit.
One would say here that confidence and trust are virtually synonymous, as can be confirmed by consulting a dictionary.
As well as the negative side of confidence, there is also the positive side. Paul speaks of “such confidence have we through the Christ towards God” (2 Corinthians 3:4) and again, “In Christ Jesus our Lord, in whom we have boldness and access in confidence by the faith of him” (Ephesians 3:12). I will not multiply passages of Scripture, as those who wish to do so can find more either from memory or by using a concordance.
The secret of true confidence is what we get in Psalm 4:5 “Offer sacrifices of righteousness, and confide in Jehovah” and similar expressions in many other Psalms.
The question may be asked: “What is the difference between confidence and faith?” They are certainly very close. The note in the J. N. Darby translation to 2 Timothy 1:12 is helpful and reads as follows: “Pisteuo, ‘believe,’ occurs in different constructions; with the dative, as here, it means, ‘to believe a person or thing;’... followed by eis with an accusative, as frequently in John, it is to believe on a person as an object of faith as John 14:1... Followed by epi with an accusative, it goes on to the idea of confidence: I rest my faith on him, yet with a more general idea of looking to him with this confidence.”
What is important for a Christian is to (1) Believe in God, that is accept He will only say the truth and (2) as a consequence, believe what he says. Adam and Eve failed in this and consequently disobeyed God. What the acceptance of the Gospel does is reverse this so that we now have the “obedience of faith” (Romans 1:5). Abraham believed God (Romans 4:3) which is the opposite of unbelief, or, as it might be put, faith in contrast to infidelity. A Christian believes that Christ died for his sins and that he is justified by faith without works. However, the question may arise as to how much real confidence has he that God will do what is right about everything (Consider Genesis 18:25 “Will not the Judge of all the earth do right?”) and not just in the matter of his salvation. When things go wrong in our lives does our confidence in God begin to waver, or are we like behemoth (Job 40:23) and are still confident in all circumstances? “The righteous trusteth (or ‘is full of confidence’) [even] in his death” (Proverbs 14:32). I expect that most of us would realise that we come short. However, let us heed the exhortation in Hebrews 10:35 “Cast not away therefore your confidence, which has great recompense”.