Jn 10:27-28, Jn 17:12, Jn 18:9, Jn 3:15-16
The work of God is to believe in the One whom God has sent. That is, believing that Jesus is the Christ. (Jn 6:29)
Jn 6:29 Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent.
Also, it is God's will that people believe in Jesus as the Son of God and the Christ to receive eternal life. (Jn 6:40)
Jn 6:40 And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life: and I will raise him up at the last day.
Also, God's will is to find and save all those entrusted to us. (Jn 6:39, Jn 10:27-28, Jn 17:12, Jn 18:9)
Jn 6:39 And this is the Father's will which hath sent me, that of all which he hath given me I should lose nothing, but should raise it up again at the last day.
Jn 10:27 My sheep hear my voice, and I know them, and they follow me: 28 And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand.
Jn 17:12 While I was with them in the world, I kept them in thy name: those that thou gavest me I have kept, and none of them is lost, but the son of perdition; that the scripture might be fulfilled.
Jn 18:9 That the saying might be fulfilled, which he spake, Of them which thou gavest me have I lost none.
In order to save us, God sent His only begotten Son, Jesus, to this earth to do the work of Christ. (Jn 3:15-16)
Jn 3:15 That whosoever believeth in him should not perish, but have eternal life. 16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.