John 20:30 And many other signs truly did Jesus in the presence of his disciples, which are not written in this book:
31 But these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name.
Mark 9:23 Jesus said unto him, If thou canst believe, all things are possible to him that believeth.
Matthew 19:26 But Jesus beheld them, and said unto them, With men this is impossible; but with God all things are possible.
Essentially the same meaning is found in Mark 10:27
Mark 10:27 And Jesus looking upon them saith, With men it is impossible, but not with God: for with God all things are possible.
In life, oftentimes situations arise when something is impossible for us, or for others, in the natural.
It may a case of a disease that is incurable.
Exodus 3:14 And God said unto Moses, I AM THAT I AM: and he said, Thus shalt thou say unto the children of Israel, I AM hath sent me unto you.
15 And God said moreover unto Moses, Thus shalt thou say unto the children of Israel, The LORD God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob, hath sent me unto you: this is my name for ever, and this is my memorial unto all generations.
Job 22:21 Acquaint now thyself with him, and be at peace: thereby good shall come unto thee.
James 2:17 Even so faith, if it hath not works, is dead, being alone.
The New Testament refers to "believers", "the believers", and "them that believe". These expressions carry the distinct but overlapping meanings of membership of the community of believers, and also connotes the type of belief that results in this membership. Note that it can and does happen that there are "little ones" that believe. (See Matthew 18:6, Mark 9:42)