John Calvin's Bible Commentary
Jeremiah 44:29
Jeremiah seals his prophecy by adding a sign which yet was to be coincident with it. It was not then, as they say, a premonstrative sign. And doubtless the Jews were wholly unworthy that God should shew them anything extraordinary; but this sign was only added, that they might know that they in vain trusted in the protection of Egypt, and also that every excuse might be taken away.
This brief notice may perhaps be obscure. We shall therefore refer to a distinction that exists: some signs precede the time and order of things, but others are connected with the events themselves. The signs which precede events avail to prepare the minds of the faithful, so that they may not doubt but that God will do what he has promised, as when Gideon sought a sign from God, and it was granted to him; the ground was wet with dew, while the fleece remained dry; and then the fleece remained dry when the ground was wet. (Jude 6:36.) By this sign Gideon was encouraged to proceed in his course, when before doubt made him inert Gideon was torpid, but when he saw by this miracle that victory would be given him, he boldly undertook the work assigned to him. The greatest portion of signs are of this kind. But there are other signs which do not precede events, but shew that when the time is fulfilled the events have been truly predicted, as when God said to Moses,
“This sign I give thee, that after ye have come out of Egypt ye shall sacrifice to me in this mountain.” (Exodus 3:12)
Neither Moses nor the people could know anything by that sign before they had departed from Egypt. But after they were delivered they there gave thanks on the third day to God their Redeemer.
Hence signs refer sometimes to past time, and sometimes to what is future. Those which refer to the future are such as we call premonstrative, as the case was with Gideon, who took up arms with alacrity, because he knew that he was fighting under God’s banner; and he was fully persuaded of a victory when he understood that God would be his leader.