Some people think that there is a difference in God between the Old and New Testaments. God did not change, only the specifics of the covenant. God loved man and hated sin in the Old Testament, and He still does both. The blood of Jesus Christ fulfills the symbolism of animal sacrifices and provides remission of sin (Mt 26:28, Heb 8-10), but there was love and mercy in the Old Testament, and there is still judgment in the New Testament. In fact, in some ways judgment is even more serious in the New Testament because our opportunity is greater (Mt 11:21-24, Lk 12:48, Lk 19:44, Heb 6:1-9, 2Pet 2:20). Also, judgment deferred can be more dangerous than when it is swift, because people think they are getting away with it (Ecc 8:11).
There are 3 Greek words for love - agape, phileo, and eros. Eros refers to sexual love and is not translated love in the Bible. Phileo refers to brotherly love between people. Agape is a word that does not appear in secular Greek literature until after the New Testament was written. It was coined by God for the Bible. Agape describes altruistic, selfless, sacrificial love. Jesus said it well when He said, "Greater love hath no man than this, that a man lay down his life for his friends (Jn 15:13)." This is of course what Jesus did, but He went even further. "But God commendeth His love toward us, in that, while we were yet sinners, Christ died for us (Rom 5:8)." Our sin made us God's enemies (Rom 5:10, Col 1:21), yet He still loved us so much He died for us. Who would die for their friends, let alone their enemies?
God did not demonstrate His love for us by sending someone else to die. That is not love. He did it Himself (Is 59:1-2 & 16-17, Acts 20:28). When the Bible says the Father sent the Son, that is not talking about two persons. The Son was the man God came in (Jn 14:1-3 & 14, Jn 14:7-11, 2Cor 5:19, Col 2:9, 1Tim 3:16). The Son was begotten in time (Ps 2:7, Jn 3:16, Gal 4:4). He only existed before that literally as God the Father, and prophetically as the Son. God loves us so much He humbled Himself and became a man so He could have a body and blood to sacrifice for us (Phil 2:5-11, Heb 10:5). The prophets were sent by God, but that does not mean they existed before their birth, even when God had made plans for them beforehand (Jer 1:5). God spoke of Solomon (1Chr 22:9), Josiah (1Ki 13:2), and Cyrus (Is 44:28-45:1) by name before they were born. When God plans something, it is prophetically as though it had already happened (Rom 4:17, Eph 1:11). God knows how to bring His plan to pass (Is 55:8-11). He saw the fallen world, and planned from the beginning to come and save us (Jn 1:1-3 & 14, Eph 3:9, 1Pet 1:20, Rev 13:8,).
God is love (1Jn 4:8). This is a most basic fact about God. Yet it is also one of the most questioned things about God. People blame God for things He did not do. People hate and blame themselves for their sins and the sins of others, and they project that onto their Creator. People blame God for the suffering of the world, when it is the sin of man that brought all that. God created a beautiful, perfect world for man which was free from pain and death (Gen 1-2). God showed man how to keep it that way, and warned him of the consequences of sin (Gen 2:15-17). Sin changed all that (Gen 3). The rest of creation groans with man for deliverance from the curse of sin (Rom 8:17-23). God will restore everything the sin of man lost him, even though it was not God's fault (Rev 21:1-5, , Rev 22:1-2). If there is one thing we can be sure of, it is that God loves us. Sin distorts our view of God, but when we repent and receive God's forgiveness and healing, we can experience His love and know it is real.