If you have received Jesus Christ as your personal Savior, you can be certain of these things:
"But as many as received him, to them gave he the right to be children of God, to those that believe on his name;" (John 1:12)
"He has ... forgiven you all trespasses" (Colossians 2:13); "Justified freely by His grace through the redemption that is in Christ Jesus" (Romans 3:24).
"If anyone is in Christ, he is a new creation; old things have passed away; behold, all things have become new" (2 Corinthians 5:17).
"He who hears My word and believes in Him who sent Me has everlasting life, and shall not come into judgment, but has passed from death into life" (John 5:24).
"Having believed, you were sealed with the Holy Spirit of promise, who is the guarantee of our inheritance" (Ephesians 1:13-14)
"Therefore being justified by faith, we have peace with God through our Lord Jesus Christ" (Romans 5:1)
These things establish your eternal position before God. However, at any time, your present spiritual condition depends on your practical obedience to His Word.
Below are several things you can do to please God and grow spiritually.
"That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved." (Romans 10:9)
"Make disciples of all the nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit" (Mathew 28:19). The new believer should respond as the Ethiopian did after hearing the gospel: "what hinders me from being baptized?" (Acts 8:36)
"Obey My voice, and I will be your God, and you shall be My people. And walk in all the ways that I have commanded you, that it may be well with you" (Jeremiah 7:23). Make this commitment: by the Grace of God, I will do anything and go anywhere the Lord desires.
You need it for -
Hold no secrets from God - tell Him everything. As a redeemed child you should not be afraid to ask for anything according to His will (1 John 5:14-15). However, your requests should be coupled with praise and thanksgiving: "Be anxious for nothing, but in everything by prayer and supplication, with thanksgiving, let your requests be made known to God" (Philippians 4:6).
Do not neglect this privilege. It is the only way you can honor the Lord's final request: "Do this in remembrance of me" (Luke 22:19). You should meet with other Christians regularly and scripturally because Jesus said, "Where two or three are gathered together in My name, I am there in the midst of them" (Mathew 18:20).
You can never repay God. Nevertheless, He appreciates your gifts of time, talents, and resources. There is blessing in giving: "He who sows bountifully will also reap bountifully. So let each one gives as he purposes in his heart, not grudgingly or of necessity; for God loves a cheerful giver" (2 Corinthians 9:6-7)
Spread the good news of salvation by your walk, by your words, through public preaching, through the distribution of literature, etc. "You shall be witnesses to Me" (Acts 1:8).
Realizing that you are not saved by works (Ephesians 2:8-9), do something (as the Spirit directs) for the One who ahs done so much for you. God had more in mind for you then merely saving you from hell: "We are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them" (Ephesians 2:10).
Scripture gives a wonderful guarantee: "If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness" (1 John 1:9). It also gives a warning: "He who covers his sins will not prosper, but whoever confesses and forsakes them will have mercy" (Proverbs 28:13).
Your Christian life will be more successful if you live as though the Lord were coming at any moment: "Watch therefore, for you do not know what hour your Lord is coming" (Mathew 24:42). You will be more joyful if you anticipate His coming as "the blessed hope and glorious appearing of our great God and Savior Jesus Christ" (Titus 2:13).