1 John 4:20

“If a man say I love God, and hateth his brother, &c.] Than which profession nothing can be more contradictory, not black and white, or hot and cold in the same degree: he is a liar; it is not truth he speaks, it is a contradiction, and a thing impossible: for he that loveth not his brother whom he hath seen; his person, which might have drawn out his affection to him; and something valuable and worthy in him, which might have commanded respect; or his wants and distresses, which should have moved his pity and compassion: how can he love God whom he hath not seen? it cannot be thought he should; the thing is not reasonable to suppose; it is not possible he should; (see Gill on “<620412>1 John…”

“loveth not . . . brother whom he hath seen, how can he love God whom he hath not seen--It is easier for us, influenced as we are here by sense, to direct love towards one within the range of our senses than towards One unseen, appreciable only by faith. "Nature is prior to grace; and we by nature love things seen, before we love things unseen" [ESTIUS]. The eyes are our leaders in love. "Seeing is an incentive to love" [Å“CUMENIUS]. If we do not love the brethren, the visible representatives of God, how can we love God, the invisible One, whose children they are? The true ideal of man, lost in Adam, is realized in Christ, in whom God is revealed as He is, and man as he ought to be. Thus, by…”

“If a man say, I love God, and hateth his brother - His Christian brother; or, in a larger sense, any man. The sense is, that no man, whatever may be his professions and pretensions, can have any true love to God, unless he loves his brethren. He is a liar - Compare the notes at 1 John 1:6. It is not necessary, in order to a proper interpretation of this passage, to suppose that he “intentionally” deceives. The sense is, that this must be a false profession. For he that loveth not his brother whom he hath seen ... - It is more reasonable to expect that we should love one whom we have seen and known personally, than that we should love one whom we have not seen. The apostle is arguing from…”

“Whom he hath seen - Who is daily presented to his senses, to raise his esteem, and move his kindness or compassion toward him. 1 John 4:21”

“a man: Jo1 2:4, Jo1 3:17 not: Jo1 4:12 1 John 4:21”