Observe here, 1. What is the sum of the Christian's duty, faith and love, to believe on the name of Jesus Christ; that is, to rely upon him as our Redeemer, our Teacher, our King, our Intercessor, and to obey his great command of loving one another with a pure heart fervently.
Observe, 2. What a mighty encouragement it is to faith, that believing on Christ is constituted a duty by a plain gospel-precept, This is his commandment, for this command cuts off that vain pretence and plea of presumption. What! such a vile wretch as thou presume to believe on Christ? says Satan. Yes, says the Christian, here is a command to me so to do, yea, a command from the highest sovereignty, the contempt whereof I must answer at my utmost peril.
Observe, 3. How the command of faith, and the command of love, are linked and knit together, as if the weight of our salvation hung equally and alike upon both; as without faith it is impossible to please God, so without love it is impossible to please him also. Will no duty profit without faith? In like manner can we neither profit ourselves nor others without love: As whatever is not of faith is sin, so whatever duty we perform towards our brother, if we do it not out of love, we miss our reward. If I give all my goods to feed the poor, and have not love, I am nothing. 1Co_13:1 Lord! can we ever think this command of love small and inconsiderable, when thou hast joined the love of thine image with faith in thy dear Son? This is his commandment, that we should believe on the name of his Son, and love one another.