It is obvious that Scripture does not individually list our names in the Bible among the Elect. How can we know and be comforted that we are among the Elect?
We know that we are among the Elect by a true faith in Jesus Christ, a worshipful fear of God as our Father, a godly sorrow for sin, and a hungering and thirsting for righteousness. “The elect in due time, though in various degrees and in different measures, attain the assurance of this their eternal and unchangeable election, not by inquisitively prying into the secret and deep things of God, but by observing in themselves with a spiritual joy and holy pleasure, the infallible fruits of election pointed out in the Word of God – such as a true faith in Christ, filial fear, a godly sorrow for sin, a hungering and thirsting after righteousness, etc.” Article 12 of Canons of Dort.
We know that we are among the Elect by the Holy Spirit who so assures us that we are children of God. “For all who are being led by the Spirit of God, these are sons of God. For you have not received a spirit of slavery leading to fear again, but you have received a spirit of adoption as sons by which we cry out, “Abba! Father!” The Spirit Himself testifies with our spirit that we are children of God,” Romans 8:14-16.
We know that we are among the Elect by the Holy Spirit who makes us wholeheartedly willing and ready to live for him. 2 Peter 1:10-11 states it this way: “Therefore, brethren, be all the more diligent to make certain about His calling and choosing you; for as long as you practice these things, you will never stumble; for in this way the entrance into the eternal kingdom of our Lord and Savior Jesus Christ will be abundantly supplied to you.” So, what are “these things”? The prior verses tell us: “Now for this very reason also, applying all diligence, in your faith supply moral excellence, and in your moral excellence, knowledge, and in your knowledge, self-control, and in your self-control, perseverance, and in your perseverance, godliness, and in your godliness, brotherly kindness, and in your brotherly kindness, love.” 2 Peter 1:5-7. Notice that these qualities are also fruit of the Holy Spirit: “But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control …” Galatians 5:22-23.
Tying these last two things together, The Heidelberg Catechism, Q & A 1, states: “Because I belong to him, Christ, by his Holy Spirit, assures me of eternal life and makes me wholeheartedly willing and ready from now on to live for him.”
Reformed Doctrine Daily Devotions 