The most common complaint I hear from Christians is this. "I know God loves me, but most of the time I don't feel that love. It is not real to me."
Jude 21 lays down the solution. "Keep yourself in the love of God." That doesn't mean "feel the love of God." It means put your mind on it. It is objective truth. God loves you. It matters little how you or I feel about it. His love is always there. We internalize it by faith. We receive it by believing no matter how we feel.
Practically, how does this work? We meditate on what God has done for us. We call this preaching the gospel to ourselves. Here is what God has done. The Father chose you from before the foundation of the world (Eph. 1:4). He did this because he loves you. Then he sent his Son on a rescue mission to save you. He descended an infinite distance, clothed himself in human flesh, and lived a perfect life. Then he suffered the wrath of God in your place. It was an infinite suffering. He rose from the dead and ascended into Heaven. When he ascended he took you with him (Eph 1:20). Because he now sits at the right hand of the Father to constantly intercede for you, you can be sure that everything yesterday, today, and tomorrow is working together for your good (Rm. 8:28).
In other words, God's love is know by what he has done for you, not by how you feel about it. “It is well known that the Greek word for love in the New Testament, agapē, was not previously in common use," David Prior writes. "It was taken into the Greek of the New Testament specifically because the love of God, seen in Jesus of Nazareth, required a new word. God’s love completely transcends all human ideas or expressions of love. ‘It is a love for the utterly unworthy, a love which proceeds from a God who is love. It is a love lavished on others without a thought of whether they are worthy to receive it or not. It proceeds rather from the nature of the lover, than from any merit in the beloved’. This is the love which, according to Jesus, has to characterize and control the Christian community, if it is in any sense to be recognized as Christian and if he is to be recognized as God’s Son and the world’s Saviour.”
Increasingly, the love of God becomes real to those who preach the gospel to themselves. If you do, before you know it, you will be awash in love's "height, and depth, and breadth," until in Paul's words, you are "filled up with all the fullness of God" (Eph. 3:19).