The Spirit of Truth indwelling IN US is our witness. And this is the record, that God hath given to us eternal life, and this life is in his Son. We have been talking about all these three's bearing witness along with the eyewitnesses and even ourselves. Now John tells us what this record is we witness, and he tells us where it can be found. Practice makes perfect.
Repetitive teachings make for a sound pupil.
And if we know that he hear us, whatsoever we ask, we know that we have the petitions that we desired of him. We can know if He hears us if we know we pray according to His will , and if we know this we can know that we will have those prayers answered. If any man see his brother sin a sin which is not unto death, he shall ask, and he shall give him life for them that sin not unto death. I believe that John is speaking of different kinds of sinning here. If we see our brother, a fellow saved person in sin, we should pray for him.