2 Pet 3:18
But grow in the grace and knowledge of our Lord and Savior Jesus Christ. To him be glory both now and forever! Amen.
God wants us to grow in His grace and knowledge. Churches today are very interested in growth; first, increasing growth on church members, second, on educating for their spiritual lye of, third, on expanding churches through sending out missionaries all over the world. But, this maturity starts from one's spiritual growth. Thus, there should be maturity after one's salvation. "I planted the seed, Apollos watered it, but God made it grow. So neither he who plants nor he who waters is anything, but only God, who makes things grow"(1 Cor 3:6–7). There are three dimensions on salvation. Christians are in the process of gaining a complete salvation(Acts 2:47; 1 Cor 1:18; 2 Cor 2:15). And Christians will be saved in the future(1 Pet 1:2).
The apostle Paul said, "Until we all reach unity in the faith and in the knowledge of the Son of God and become mature, attaining to the whole measure of the fullness of Christ. Then we will no longer be infants, tossed back and forth by the waves, and blown here and there by every wind of teaching and by the cunning and craftiness of men in their deceitful scheming. Instead, speaking the truth in love, we will in all things grow up into him who is the Head, that is, Christ. From him the whole body, joined and held together by every supporting ligament, grows and builds itself up in love, as each part does its work"(Eph 4:13–16).
To grow spiritually, we should crave for a pure milk(1 Pet 2:2). The apostle John also said, "I write to you, fathers, because you have known him who is from the beginning. I write to you, young men, because you are strong, and the word of God lives in you, and you have overcome the evil one"(1 John 2:14). We should taste grace of God in His word(1 Pet 2:3). The Psalmist advised, "taste the goodness of the Lord." To taste His goodness and kindness, we should believe in Christ. Through Christ, we know God, and learn about His personality.