13 Jesus replied, “Everyone who drinks some of this water will be thirsty again. 14 But whoever drinks some of the water that I will give him will never be thirsty again, but the water that I will give him will become in him a fountain of water springing up to eternal life.”
The word “water” in the passage refers to the Holy Spirit.
“But whoever drinks some of the water that I will give him” Refers to placing one’s faith in Jesus for eternal life.
“never be thirsty again” Means that the person who has the Holy Spirit will never lose their salvation.
“will become in him a fountain of water springing up to eternal life.” A fountain continues with its water because of the depth of its source. But our salvation will continue because the source of eternal life does not spring up from us but from the Spirit of God who lives in us, whose power is endless.
24 Now to him who is able to keep them from stumbling, and to present you faultless before the presence of his glory in great joy
“Now to him who is able to keep them from stumbling” God Himself keeps those who are His from abandoning Him through His mighty power. He does this by convicting us when we commit sin and stray from his presence.
“to present you faultless” The word faultless means to be without sin [being forgiven]. But, according to the context, it is in reference to being faithful to the end and not giving up on one’s faith in Jesus Christ.