'Adhere' in the Bible

This is His commandment, that we believe [with personal faith and confident trust] in the name of His Son Jesus Christ, and [that we unselfishly] love and seek the best for one another, just as He commanded us.

We have come to know [by personal observation and experience], and have believed [with deep, consistent faith] the love which God has for us. God is love, and the one who abides in love abides in God, and God abides continually in him.

These things I have written to you who believe in the name of the Son of God [which represents all that Jesus Christ is and does], so that you will know [with settled and absolute knowledge] that you [already] have eternal life.