When one is baptized into Christ by water baptism, is it for remission of past sins only? Or is baptism for all sins (past, present, and future sins)?
"Peter said to them, "Repent, and each of you be baptized in the name of Jesus Christ for the forgiveness of your sins; and you will receive the gift of the Holy Spirit" (Acts 2:38).
Since repentance is required before baptism, a person has to turn away from sin before entering the water; therefore, baptism does not give forgiveness for sins you remain involved in. "What shall we say then? Are we to continue in sin so that grace may increase? May it never be! How shall we who died to sin still live in it?" (Romans 6:1-2).
"For in the case of those who have once been enlightened and have tasted of the heavenly gift and have been made partakers of the Holy Spirit, and have tasted the good word of God and the powers of the age to come, and then have fallen away, it is impossible to renew them again to repentance, since they again crucify to themselves the Son of God and put Him to open shame" (Hebrews 6:4-6).
Since it is possible for a Christian to fall way into sin, to the point that they can choose not to return, their past baptism does not forgive them of their future sins.
However, this does not mean that a Christian has to be baptized again each time he sins. "If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness" (I John 1:9). A Christian need to repent of any sins he gets caught up in (II Corinthians 7:10-11), admit to God that he fail, and God is willing to forgive him.