Arcana Coelestia#6870
6870. 'And this will be the sign to you that I have sent you' means the recognition that the Divine would go forth from Him. This is clear from the meaning of 'the sign' as the corroboration of truth and consequent recognition that it is indeed so; and from the meaning of 'being sent' as going forth, dealt with in 2397, 4710, 6831, so that 'being sent by God' is going forth from the Divine. It is also the Divine going forth from Him, for one who comes forth from the Divine is receptive of the Divine and extends its influence further.
John 6:39-40
39
This is the will of my Father who sent me, that of all he has given to me I should lose nothing, but should raise him up at the last day.
40
This is the will of the one who sent me, that everyone who sees the Son, and believes in him, should have eternal life; and I will raise him up at the last day."