Nice one sir, I agree with you that man's assurance shouldnt be based on what man has to give in response to love,trust,dedication etc rather it's should be focused on the essence of our existence to God and his sacrifice and fulfilment's in our life that more than every manly assurance we get, because at some point it will get wore out, outdated or valued less, so it is necessary for us to focus on God by believing in his assurance and also assuring him that we trust in him by Faith and love.