The Pharisees and Sadducees came up, and testing JESUS, they asked HIM to show them a sign from heaven.
But HE replied to them, “When it is evening, you say, ‘it will be fair weather, for the sky is red.’
“And in the morning, ‘There will be a storm today, for the sky is red and threatening.’
Do you know how to discern the appearance of the sky, but cannot discern the signs of the times?
“An evil and adulterous generation seeks after a sign; and a sign will not be given it, except the sign of Jonah.”
And HE left them and went away.
Matthew 16:1-4

In this passage of Scripture we saw religious leaders wanting JESUS to prove that HE was indeed the Messiah sent by GOD, by providing a miracle from heaven (such as when fire came down from heaven to the earth, proving Elijah was the prophet sent by The true GOD in 1 Kings 18:36-39).

Our Beloved LORD JESUS WHO had already performed many miracles up to this point, had provided sufficient proofs that HE was WHO HE claimed to be. Yet these religious leaders still did not believe in HIM. Knowing that sufficient proof of truth would never be accepted by hardened, unbelieving hearts HE simply stated “An evil and adulterous generation seeks after a sign; and a sign will not be given it, except the sign of Jonah.” This statement to the unbelieving religious leaders was expounded upon in Matthew 12:39-41:

But HE answered and said to them,
“An evil and adulterous generation craves for a sign; and yet no sign will be given to it but the sign of Jonah the prophet; for just as JONAH WAS THREE DAYS AND THREE NIGHTS IN THE BELLY OF THE SEA MONSTER
So will The SON of Man be three days and three nights in the heart of the earth
“The men of Nineveh will stand up with this generation at the judgment, and will condemn it
because they repented at the preaching of Jonah
and behold, something greater than Jonah is here

So do believers need to discern (understand or recognize) the signs of the times? Yes for many reasons, but we will only give you four:

1.  So that we are not caught off-guard; unprepared; asleep (Mrk 13:36, Rom 13:11).
We have been continually commanded to “be on the alert” (Mat 24:42-44, Mat 25:1-13, Mrk 13:32-36, Luk 12:35-40, 1 Ths 5:1-6). To be on the alert means to be watchful; extremely aware of what is going on with our surroundings.

“What I say to you I say to all, ‘Be on the alert!'”
Mark 13:37

We have been commanded to keep a careful watch over ourselves, our hearts and our lives (Pro 4:20-27, Eph 5:15-18), so that the worries of this life, the everyday events in this life, the pleasures of this life, and the deceitfulness of wealth in this life cause us to be as unexpectant and unprepared for HIS return as unbelievers (Luk 21:34-36, Mat 24:36-39, Luk 17:26-30).

2. So that we have knowledge of what we should do (Hos 4:6).
We should be like the sons of Issachar (1 Chr 12:32), we should understand the times we are living in, and have knowledge of what GOD’s people should do, as demonstrated by the following Scriptures:

“By smooth words he will turn to godlessness those who act wickedly toward the covenant
But the people who know their GOD will display strength and take action.
Daniel 11:32

“Go therefore and make disciples of all the nations
Baptizing them in the name of The FATHER and The SON and The Holy SPIRIT
Teaching them to observe all that I commanded you
And lo, I am with you always, even to the end of the age.”
Matthew 28:19-20

And HE said to them, “Go into all the world and preach the gospel to all creation”
Mark 16:15

Preach the word
Be ready in season and out of season
Reprove, rebuke, exhort, with great patience and instruction
2 Tim 4:2

But you, be sober in all things, endure hardship, do the work of an evangelist, fulfill your ministry.
2 Timothy 4:5

Since all these things are to be destroyed in this way,
What sort of people ought you to be in holy conduct and godliness
2 Peter 3:11

3. So that we are able to give understanding to others what is going on (Dan 11:33).
Our Beloved LORD GOD is a friend to those who love and obey HIM (Pro 18:24, Jhn 15:14-15, Jam 2:23). HE makes known to HIS friends:
    • HIS Will (Rom 12:2, Col 1:9-10, 1 Ths 4:3-8)
    • HIS Ways (Psa 25:8-9, Psa 32:8, Psa 119:3)
    • HIS Heart (Jer 31:3, 1 Tim 2:3-4, 2 Pet 3:9)
    • HIS Plans (Gen 6:13, Gen 18:17-33, 1 Sam 3:11-14, Psa 33:11, Amo 3:7)
So that we may know and understand HIM (Jer 9:24, Exd 33:13↔Psa 103:7, Gal 6:14).

As friends of GOD, we are also called to be HIS faithful servants and messengers; making HIS WORD known to others for their salvation (Mrk 16:15-16, Rom 10:13-18), for their growth by gaining understanding (Ezr 8:1-8, Mat 28:19-20), for their welfare concerning the consequences of sin (Jer 23:22, Jer 35:15, Jam 5:19-20), and for their knowledge of various events and circumstances (Mrk 13:23, Jhn 15:18-19, 1 Ths 3:4, 1 Pet 4:12-19).

Will we be able to give understanding to everyone? No, the wicked will not understand (Dan 12:10). They will not hear The WORDS of JESUS CHRIST (Jhn 8:43-47) because they refuse to listen (Isa 30:10, 1 Jhn 4:5-6), they reject the truth (2 Ths 2:10-12, 2 Tim 4:3-4) and mock those who bring it (2 Pet 3:3-4, Jud 1:18-19).

4. So that we are not frightened but recognize the events that lead to our redemption (Mat 24:6, Mat 24:32-33, Luk 21:9).
HE has told us everything in advance (Mrk 13:23), so while men who do not know HIM or HIS plans are fainting from fear of what appears to be happening (Luk 21:26), we should be expectantly looking for HIS return (Luk 12:35-40, Luk 21:29-36).

“Take heed, keep on the alert; for you do not know when the appointed time will come.
Mark 13:33