John Calvin's Bible Commentary
Jeremiah 42:6
As the Jews spoke feignedly by assuming a character not their own, they profaned God’s name. But if we desire to prove our fidelity to God, the only way of acting is, to regard his word as binding, whether it be agreeable or otherwise, and never to murmur, as the ungodly do; for when God would have a yoke laid on them, they complain that his doctrine is too hard and burdensome. Away, then, with all those things which can render God’s word unacceptable to us, if we desire to give a sure proof of our fidelity. Hence they said, Whether it be good or evil, what God will lay down we will obey his voice.
They afterwards added, For which we send thee to him (127) Here they still further cast themselves into toils. Jeremiah did not in express words require them to make an oath; they yet did make an oath; and then in various ways still more bound themselves over to punishment, if they became perjurers. They now shew that it would be a two-fold crime, should they disobey God; how? Had the Prophet been sent to them, they might have made excuses; though vain, they might yet have something to allege; but when they of their own accord asked God, when they offered of themselves to do this, and promised to be obedient in all things, it is evident that unless afterwards they acted according to their pledged faith, they must have been more inexcusable, because they tempted God: for who induced them to come to the Prophet? We hence see that God extorted from them what doubled their crime. But the more hypocrites attempt by disguises to conceal their impiety, the faster they bind themselves, and the more they kindle God’s wrath against themselves.
They then added, That it may be well with us when we obey the voice of Jehovah By this circumstance also they aggravated their crime. For if the Prophet had promised them a prosperous issue, they might not have believed; in that case they would have indeed sinned; but their wicked-ness would have been more tolerable than when they themselves had spoken, as though they were the organs of the Holy Spirit; they said themselves, It shall be well with us; it will be our chief happiness to follow the voice of God and to obey him. As, then, they thus protested to God and the Prophet, that they might appear to be God’s faithful servants, the greater condemnation they brought on themselves; for if they believed that nothing would turn out happily, except according to God’s command, how was it that they did not submit to God? why did they despise what was afterwards said by the Prophet? But as we have already said, as they deceived themselves by dealing falsely with God and profaning his holy name, let us learn and know that we can in no other way expect a happy issue in all that we do, but by obeying the voice of God; for whatever men may attempt of themselves, it will be accursed before God. This, then, is our only sure hope, that when we attempt nothing but what is according to God’s word, there will be a good and happy issue, though many things may happen otherwise than we hope or think.