Blood, sweat and tears are three elements prepared by the body specifically to maintain life, temperature and protection of the skin, and lubrication of the eyes. They are part of the wonderful working of our terrestrial "tent", designed according to the infinite wisdom of our God. When our first ancestors sinned, in the Garden of Eden, these three elements acquired, beyond this vital use, a still more ample significance, as we shall see below.
Sin brought spiritual death to the human being, which is loss of fellowship with God. Following this, eventual physical death also became a reality. The curse of God came upon the rest of creation, which God had earlier declared to be "very good". Adam and Eve found themselves naked and tried to cover themselves with leaves before appearing before God. But the Lord God showed them that it was necessary more than this: He made garments of skin for Adam and his wife and clothed them.
We learn another lesson with this, but what interests us most here is that, for the first time, there was death: the skin came from animals, and the animals died so that Adam and Eve could cover themselves. The nakedness of Adam and Eve cost the lives of these animals. It is the first example of "atonement", in which the blood (life) of animals was spilled to cover (or "atone for") the sin of somebody. It is a type of the real atonement made by the death of the Son of God.
Blood, the vital element, became a symbol of life itself. God forbade murder, or "shedding of blood", because God requires the lifeblood of every man for Himself (Genesis 9:5), but allowed animals to be killed so long as their flesh was not eaten with their blood (Genesis 9:4). Blood is still a symbol of life today, in the common language.
The law given through Moses to the children of Israel maintained the prohibition to drink blood, but conceded that the blood of certain animals, considered ritualistically "clean", should be used for cleansing and atonement of the sins of the children of Israel: "according to the law almost all things are purified with blood, and without shedding of blood there is no remission." (Hebrews 9:22).
At the beginning of the church, there was debate in Jerusalem as to how far Gentiles should be submitted to the law of Moses, after which the apostles and elders wrote a letter to the Gentile Christians advising that "it seemed good to the Holy Spirit, and to us, to lay upon you no greater burden than these necessary things: that you abstain from things offered to idols, from blood, from things strangled, and from sexual immorality. If you keep yourselves from these, you will do well" (Acts 15:28-29 - NKJV). This decision, concerning drinking blood, is one of the first commandments of God, given much earlier than the law of Moses, and is not ceremonial or temporary as some people like to think. We really would do well to obey it.
At the time appointed by God, the Lord Jesus Christ spilled His own blood: He bled when he suffered the scourging which preceded the crucifixion. The procedure of this cruel method of execution included preliminary scourging which caused great bleeding, weakening, dehydrating and so abbreviating the death of the condemned who might be hanging for various days. Beside the scourging, the soldiers crowned the Lord with a crown of thorns, to ridicule Him (Matthew 27:26-31, Mark 15:15-20, John 19:1). They were far from knowing that He was in reality the king of the universe. Continuing to bleed, He suffered the wounds of the nails on His hands and feet. Already dead, one of the soldiers perforated the side of the Lord with a lance to be sure, and blood and water immediately flowed, a conclusive evidence (comp. Psalm 69:20).
The death of the Lord Jesus resulted from the pouring out of His blood. The moment of death was determined by He Himself, when He exclaimed "It is finished!" and "Father, into Your hands I commit My spirit." Luke 23:46 (NKJV). The symbolism of blood with physical life was consecrated, and the two terms are interchangeable in the New Testament. Since that moment He can save from the penalty of sin anyone who trusts in Him, for His blood purifies us from all sin (1 John 1:7).
Our Saviour Jesus Christ left us another symbol of His blood, reminding us of His death for our sins, which is the cup in the Lord's Supper: we must all take of it, for this is His wish and commandment (Matthew 26:27,28, etc.).
Sweat is for the first time mentioned in Genesis 3:19: "In the sweat of your face you shall eat bread" Genesis 3:19 (NKJV). Sweat, essential for the comfort of the skin when the temperature around us increases (Ezekiel 44:18), became a symbol of the effort of intensive work, of anguish and suffering, still used in the language of today.
In Luke, chapter 22 and verse 44, we read that, in the garden of Gethsemani on the mount of Olives, shortly before being taken prisoner, "being in agony, He prayed more earnestly. Then His sweat became like great drops of blood falling down to the ground." Luke 22:44 (NKJV). It is the only biblical text which tells us this and it has given rise to various interpretations, specially because there is an old translation, but still used, which unduly omits the word "like", and many commentators work hard to explain how He could have exhaled drops of blood instead of sweat!
Luke, being a medical professional, observed and told us this detail. It isn't difficult to understand that sweat in abundance drops, that blood forms bigger drops because of the rapid process of coagulation, therefore the drops of sweat at that time were large as if they were clotted blood. No doubt the Lord was in great mental suffering, knowing that He was to suffer the terrible wrath of His Father and would be forsaken by Him because of the sin of the world which he took upon Himself (Matthew 27:46). This was the sweat of extreme affliction.
Tears, so important for protecting the eyes, flow in profusion on occasions of strong emotions, specially those of great sadness. No doubt weeping accompanied by tears started with sin, because before, in perfect communion with God, there was no motive for sadness. Tears are often mentioned in the Old Testament in relation with own sin, or that of others. Tears because of death, sorrow and crying is one of the last things mentioned in the Bible which will no more exist in the new heavens and the new earth (Revelation 21:4).
Jesus Christ experienced strong emotions among the people who surrounded Him when He was covered in His human body, until He delivered that body on the cross of Calvary as an acceptable sacrifice for sin to God. He felt deep compassion for humanity. He wept when He came to the tomb of Lazarus, in sympathy with those who lamented his death there (John 11:35), and also wept over Jerusalem because of the unbelief of its inhabitants and the days of terrible persecution and destruction which would come upon it (Luke 19:41). At the garden of Gethsemani He was sorrowful and deeply distressed "even to death" (Matthew 26:37-38), and we read that He "offered up prayers and supplications, with vehement cries and tears… " (Hebrews 5:7 - NKJV).
We shall also go through moments of great sorrow and even anguish while we are in this world, for we are not better than our supreme Master. Let us remember His words: "Blessed are those who mourn, for they shall be comforted" (Matthew 5:4 - NKJV), and those of Peter: "rejoice to the extent that you partake of Christ's sufferings, that when His glory is revealed, you may also be glad with exceeding joy. 14 If you are reproached for the name of Christ, blessed are you, for the Spirit of glory and of God rests upon you. On their part He is blasphemed, but on your part He is glorified" (1 Peter 4:13-14 - NKJV). Affliction caused by our faithfulness to the name of Christ is proof that the Spirit of the glory of God rests upon us. This should make us glad, for we are blessed, and we shall rejoice when His glory is revealed when He returns to earth. Our joy will never be interrupted, "God will wipe away every tear from their eyes; there shall be no more death, nor sorrow, nor crying. There shall be no more pain, for the former things have passed away" (Revelation 21:4 - NKJV).